path: root/browser/components/urlbar/docs/telemetry.rst

Telemetry
=========

This section describes existing telemetry probes measuring interaction with the
Address Bar.

For telemetry specific to Firefox Suggest, see the
:doc:`firefox-suggest-telemetry` document.

.. toctree::
   :caption: Table of Contents

   telemetry

Histograms
----------

PLACES_AUTOCOMPLETE_1ST_RESULT_TIME_MS
  This probe tracks the amount of time it takes to get the first result.
  It is an exponential histogram with values between 5 and 100.

PLACES_AUTOCOMPLETE_6_FIRST_RESULTS_TIME_MS
  This probe tracks the amount of time it takes to get the first six results.
  It is an exponential histogram with values between 50 and 1000.

FX_URLBAR_SELECTED_RESULT_METHOD
  This probe tracks how a result was picked by the user from the list.
  It is a categorical histogram with these values:

  - ``enter``
    The user pressed Enter without selecting a result first.
    This most likely happens when the user confirms the default preselected
    result (aka *heuristic result*), or when they select with the keyboard a
    one-off search button and confirm with Enter.
  - ``enterSelection``
    The user selected a result, but not using Tab or the arrow keys, and then
    pressed Enter. This is a rare and generally unexpected event, there may be
    exotic ways to select a result we didn't consider, that are tracked here.
    Look at arrowEnterSelection and tabEnterSelection for more common actions.
  - ``click``
    The user clicked on a result.
  - ``arrowEnterSelection``
    The user selected a result using the arrow keys, and then pressed Enter.
  - ``tabEnterSelection``
    The first key the user pressed to select a result was the Tab key, and then
    they pressed Enter. Note that this means the user could have used the arrow
    keys after first pressing the Tab key.
  - ``rightClickEnter``
    Before QuantumBar, it was possible to right-click a result to highlight but
    not pick it. Then the user could press Enter. This is no more possible.

FX_URLBAR_ZERO_PREFIX_DWELL_TIME_MS
  This probe records the amount of time the zero-prefix view was shown; that is,
  the time from when it was opened to the time it was closed. "Zero-prefix"
  means the search string was empty, so the zero-prefix view is the view that's
  shown when the user clicks in the urlbar before typing a search string. Often
  it's also called the "top sites" view since normally it shows the user's top
  sites. This is an exponential histogram whose values range from 0 to 60,000
  with 50 buckets. Values are in milliseconds. This histogram was introduced in
  Firefox 110.0 in bug 1806765.

Scalars
-------

urlbar.abandonment
  A uint recording the number of abandoned engagements in the urlbar. An
  abandonment occurs when the user begins using the urlbar but stops before
  completing the engagement. This can happen when the user clicks outside the
  urlbar to focus a different part of the window. It can also happen when the
  user switches to another window while the urlbar is focused.

urlbar.engagement
  A uint recording the number of engagements the user completes in the urlbar.
  An engagement occurs when the user navigates to a page using the urlbar, for
  example by picking a result in the urlbar panel or typing a search term or URL
  in the urlbar and pressing the enter key.

urlbar.impression.*
  A uint recording the number of impression that was displaying when user picks
  any result.

  - ``autofill_about``
    For about-page type autofill.
  - ``autofill_adaptive``
    For adaptive history type autofill.
  - ``autofill_origin``
    For origin type autofill.
  - ``autofill_other``
    Counts how many times some other type of autofill result that does not have
    a specific scalar was shown. This is a fallback that is used when the code is
    not properly setting a specific autofill type, and it should not normally be
    used. If it appears in the data, it means we need to investigate and fix the
    code that is not properly setting a specific autofill type.
  - ``autofill_preloaded``
    For preloaded site type autofill.
  - ``autofill_url``
    For url type autofill.

urlbar.tips
  This is a keyed scalar whose values are uints and are incremented each time a
  tip result is shown, a tip is picked, and a tip's help button is picked. The
  keys are:

  - ``intervention_clear-help``
    Incremented when the user picks the help button in the clear-history search
    intervention.
  - ``intervention_clear-picked``
    Incremented when the user picks the clear-history search intervention.
  - ``intervention_clear-shown``
    Incremented when the clear-history search intervention is shown.
  - ``intervention_refresh-help``
    Incremented when the user picks the help button in the refresh-Firefox
    search intervention.
  - ``intervention_refresh-picked``
    Incremented when the user picks the refresh-Firefox search intervention.
  - ``intervention_refresh-shown``
    Incremented when the refresh-Firefox search intervention is shown.
  - ``intervention_update_ask-help``
    Incremented when the user picks the help button in the update_ask search
    intervention, which is shown when there's a Firefox update available but the
    user's preference says we should ask them to download and apply it.
  - ``intervention_update_ask-picked``
    Incremented when the user picks the update_ask search intervention.
  - ``intervention_update_ask-shown``
    Incremented when the update_ask search intervention is shown.
  - ``intervention_update_refresh-help``
    Incremented when the user picks the help button in the update_refresh search
    intervention, which is shown when the user's browser is up to date but they
    triggered the update intervention. We show this special refresh intervention
    instead.
  - ``intervention_update_refresh-picked``
    Incremented when the user picks the update_refresh search intervention.
  - ``intervention_update_refresh-shown``
    Incremented when the update_refresh search intervention is shown.
  - ``intervention_update_restart-help``
    Incremented when the user picks the help button in the update_restart search
    intervention, which is shown when there's an update and it's been downloaded
    and applied. The user needs to restart to finish.
  - ``intervention_update_restart-picked``
    Incremented when the user picks the update_restart search intervention.
  - ``intervention_update_restart-shown``
    Incremented when the update_restart search intervention is shown.
  - ``intervention_update_web-help``
    Incremented when the user picks the help button in the update_web search
    intervention, which is shown when we can't update the browser or possibly
    even check for updates for some reason, so the user should download the
    latest version from the web.
  - ``intervention_update_web-picked``
    Incremented when the user picks the update_web search intervention.
  - ``intervention_update_web-shown``
    Incremented when the update_web search intervention is shown.
  - ``tabtosearch-shown``
    Increment when a non-onboarding tab-to-search result is shown, once per
    engine per engagement. Please note that the number of times non-onboarding
    tab-to-search results are picked is the sum of all keys in
    ``urlbar.searchmode.tabtosearch``. Please also note that more detailed
    telemetry is recorded about both onboarding and non-onboarding tab-to-search
    results in urlbar.tabtosearch.*. These probes in ``urlbar.tips`` are still
    recorded because ``urlbar.tabtosearch.*`` is not currently recorded
    in Release.
  - ``tabtosearch_onboard-shown``
    Incremented when a tab-to-search onboarding result is shown, once per engine
    per engagement. Please note that the number of times tab-to-search
    onboarding results are picked is the sum of all keys in
    ``urlbar.searchmode.tabtosearch_onboard``.
  - ``searchTip_onboard-picked``
    Incremented when the user picks the onboarding search tip.
  - ``searchTip_onboard-shown``
    Incremented when the onboarding search tip is shown.
  - ``searchTip_persist-picked``
    Incremented when the user picks the urlbar persisted search tip.
  - ``searchTip_persist-shown``
    Incremented when the url persisted search tip is shown.
  - ``searchTip_redirect-picked``
    Incremented when the user picks the redirect search tip.
  - ``searchTip_redirect-shown``
    Incremented when the redirect search tip is shown.

urlbar.searchmode.*
  This is a set of keyed scalars whose values are uints incremented each
  time search mode is entered in the Urlbar. The suffix on the scalar name
  describes how search mode was entered. Possibilities include:

  - ``bookmarkmenu``
    Used when the user selects the Search Bookmarks menu item in the Library
    menu.
  - ``handoff``
    Used when the user uses the search box on the new tab page and is handed off
    to the address bar. NOTE: This entry point was disabled from Firefox 88 to
    91. Starting with 91, it will appear but in low volume. Users must have
    searching in the Urlbar disabled to enter search mode via handoff.
  - ``keywordoffer``
    Used when the user selects a keyword offer result.
  - ``oneoff``
    Used when the user selects a one-off engine in the Urlbar.
  - ``shortcut``
    Used when the user enters search mode with a keyboard shortcut or menu bar
    item (e.g. ``Accel+K``).
  - ``tabmenu``
    Used when the user selects the Search Tabs menu item in the tab overflow
    menu.
  - ``tabtosearch``
    Used when the user selects a tab-to-search result. These results suggest a
    search engine when the search engine's domain is autofilled.
  - ``tabtosearch_onboard``
    Used when the user selects a tab-to-search onboarding result. These are
    shown the first few times the user encounters a tab-to-search result.
  - ``topsites_newtab``
    Used when the user selects a search shortcut Top Site from the New Tab Page.
  - ``topsites_urlbar``
    Used when the user selects a search shortcut Top Site from the Urlbar.
  - ``touchbar``
    Used when the user taps a search shortct on the Touch Bar, available on some
    Macs.
  - ``typed``
    Used when the user types an engine alias in the Urlbar.
  - ``other``
    Used as a catchall for other behaviour. We don't expect this scalar to hold
    any values. If it does, we need to correct an issue with search mode entry
    points.

  The keys for the scalars above are engine and source names. If the user enters
  a remote search mode with a built-in engine, we record the engine name. If the
  user enters a remote search mode with an engine they installed (e.g. via
  OpenSearch or a WebExtension), we record ``other`` (not to be confused with
  the ``urlbar.searchmode.other`` scalar above). If they enter a local search
  mode, we record the English name of the result source (e.g. "bookmarks",
  "history", "tabs"). Note that we slightly modify the engine name for some
  built-in engines: we flatten all localized Amazon sites (Amazon.com,
  Amazon.ca, Amazon.de, etc.) to "Amazon" and we flatten all localized
  Wikipedia sites (Wikipedia (en), Wikipedia (fr), etc.) to "Wikipedia". This
  is done to reduce the number of keys used by these scalars.

urlbar.picked.*
  This is a set of keyed scalars whose values are uints incremented each
  time a result is picked from the Urlbar. The suffix on the scalar name
  is the result type. The keys for the scalars above are the 0-based index of
  the result in the urlbar panel when it was picked.

  .. note::
    Available from Firefox 84 on. Use the *FX_URLBAR_SELECTED_** histograms in
    earlier versions.

  .. note::
    Firefox 102 deprecated ``autofill`` and added ``autofill_about``,
    ``autofill_adaptive``, ``autofill_origin``, ``autofill_other``,
    ``autofill_preloaded``, and ``autofill_url``.

  Valid result types are:

  - ``autofill``
    This scalar was deprecated in Firefox 102 and replaced with
    ``autofill_about``, ``autofill_adaptive``, ``autofill_origin``,
    ``autofill_other``, ``autofill_preloaded``, and ``autofill_url``. Previously
    it was recorded in each of the cases that the other scalars now cover.
  - ``autofill_about``
    An autofilled "about:" page URI (e.g., about:config). The user must first
    type "about:" to trigger this type of autofill.
  - ``autofill_adaptive``
    An autofilled URL from the user's adaptive history. This type of autofill
    differs from ``autofill_url`` in two ways: (1) It's based on the user's
    adaptive history, a particular type of history that associates the user's
    search string with the URL they pick in the address bar. (2) It autofills
    full URLs instead of "up to the next slash" partial URLs. For more
    information on this type of autofill, see this `adaptive history autofill
    document`_.
  - ``autofill_origin``
    An autofilled origin_ from the user's history. Typically "origin" means a
    domain or host name like "mozilla.org". Technically it can also include a
    URL scheme or protocol like "https" and a port number like ":8000". Firefox
    can autofill domain names by themselves, domain names with schemes, domain
    names with ports, and domain names with schemes and ports. All of these
    cases count as origin autofill. For more information, see this `adaptive
    history autofill document`_.
  - ``autofill_other``
    Counts how many times some other type of autofill result that does not have
    a specific keyed scalar was picked at a given index. This is a fallback that
    is used when the code is not properly setting a specific autofill type, and
    it should not normally be used. If it appears in the data, it means we need
    to investigate and fix the code that is not properly setting a specific
    autofill type.
  - ``autofill_preloaded``
    An autofilled `preloaded site`_. The preloaded-sites feature (as it relates
    to this telemetry scalar) has never been enabled in Firefox, so this scalar
    should never be recorded. It can be enabled by flipping a hidden preference,
    however. It's included here for consistency and correctness.
  - ``autofill_url``
    An autofilled URL or partial URL from the user's history. Firefox autofills
    URLs "up to the next slash", so to trigger URL autofill, the user must first
    type a domain name (or trigger origin autofill) and then begin typing the
    rest of the URL (technically speaking, its path). As they continue typing,
    the URL will only be partially autofilled up to the next slash, or if there
    is no next slash, to the end of the URL. This allows the user to easily
    visit different subpaths of a domain. For more information, see this
    `adaptive history autofill document`_.
  - ``bookmark``
    A bookmarked URL.
  - ``dynamic``
    A specially crafted result, often used in experiments when basic types are
    not flexible enough for a rich layout.
  - ``extension``
    Added by an add-on through the omnibox WebExtension API.
  - ``formhistory``
    A search suggestion from previous search history.
  - ``history``
    A URL from history.
  - ``keyword``
    A bookmark keyword.
  - ``quickaction``
    A QuickAction.
  - ``quicksuggest``
    A Firefox Suggest (a.k.a. quick suggest) suggestion.
  - ``remotetab``
    A tab synced from another device.
  - ``searchengine``
    A search result, but not a suggestion. May be the default search action
    or a search alias.
  - ``searchsuggestion``
    A remote search suggestion.
  - ``switchtab``
    An open tab.
  - ``tabtosearch``
    A tab to search result.
  - ``tip``
    A tip result.
  - ``topsite``
    An entry from top sites.
  - ``unknown``
    An unknown result type, a bug should be filed to figure out what it is.
  - ``visiturl``
    The user typed string can be directly visited.

  .. _adaptive history autofill document: https://docs.google.com/document/d/e/2PACX-1vRBLr_2dxus-aYhZRUkW9Q3B1K0uC-a0qQyE3kQDTU3pcNpDHb36-Pfo9fbETk89e7Jz4nkrqwRhi4j/pub
  .. _origin: https://html.spec.whatwg.org/multipage/origin.html#origin
  .. _preloaded site: https://searchfox.org/mozilla-central/source/browser/components/urlbar/UrlbarProviderPreloadedSites.jsm

urlbar.picked.searchmode.*
  This is a set of keyed scalars whose values are uints incremented each time a
  result is picked from the Urlbar while the Urlbar is in search mode. The
  suffix on the scalar name is the search mode entry point. The keys for the
  scalars are the 0-based index of the result in the urlbar panel when it was
  picked.

  .. note::
    These scalars share elements of both ``urlbar.picked.*`` and
    ``urlbar.searchmode.*``. Scalar name suffixes are search mode entry points,
    like ``urlbar.searchmode.*``. The keys for these scalars are result indices,
    like ``urlbar.picked.*``.

  .. note::
    These data are a subset of the data recorded by ``urlbar.picked.*``. For
    example, if the user enters search mode by clicking a one-off then selects
    a Google search suggestion at index 2, we would record in **both**
    ``urlbar.picked.searchsuggestion`` and ``urlbar.picked.searchmode.oneoff``.

urlbar.tabtosearch.*
  This is a set of keyed scalars whose values are uints incremented when a
  tab-to-search result is shown, once per engine per engagement. There are two
  sub-probes: ``urlbar.tabtosearch.impressions`` and
  ``urlbar.tabtosearch.impressions_onboarding``. The former records impressions
  of regular tab-to-search results and the latter records impressions of
  onboarding tab-to-search results. The key values are identical to those of the
  ``urlbar.searchmode.*`` probes: they are the names of the engines shown in the
  tab-to-search results. Engines that are not built in are grouped under the
  key ``other``.

  .. note::
    Due to the potentially sensitive nature of these data, they are currently
    collected only on pre-release version of Firefox. See bug 1686330.

urlbar.zeroprefix.abandonment
  A uint recording the number of abandonments of the zero-prefix view.
  "Zero-prefix" means the search string was empty, so the zero-prefix view is
  the view that's shown when the user clicks in the urlbar before typing a
  search string. Often it's called the "top sites" view since normally it shows
  the user's top sites. "Abandonment" means the user opened the zero-prefix view
  but it was closed without the user picking a result inside it. This scalar was
  introduced in Firefox 110.0 in bug 1806765.

urlbar.zeroprefix.engagement
  A uint recording the number of engagements in the zero-prefix view.
  "Zero-prefix" means the search string was empty, so the zero-prefix view is
  the view that's shown when the user clicks in the urlbar before typing a
  search string. Often it's called the "top sites" view since normally it shows
  the user's top sites. "Engagement" means the user picked a result inside the
  view. This scalar was introduced in Firefox 110.0 in bug 1806765.

urlbar.zeroprefix.exposure
  A uint recording the number of times the user was exposed to the zero-prefix
  view; that is, the number of times it was shown. "Zero-prefix" means the
  search string was empty, so the zero-prefix view is the view that's shown when
  the user clicks in the urlbar before typing a search string. Often it's called
  the "top sites" view since normally it shows the user's top sites. This scalar
  was introduced in Firefox 110.0 in bug 1806765.

places.*
  This is places related telemetry.

  Valid result types are:

  - ``sponsored_visit_no_triggering_url``
    Number of sponsored visits that could not find their triggering URL in
    history. We expect this to be a small number just due to the navigation layer
    manipulating URLs. A large or growing value may be a concern.

Search Engagement Telemetry
---------------------------

The search engagement telemetry provided since Firefox 110 is is recorded using
Glean events. Because of the data size, these events are collected only for a
subset of the population, using the Glean Sampling feature. Please see the
following documents for the details.

  - `Engagement`_ :
    It is defined as a completed action in urlbar, where a user picked one of
    the results.
  - `Abandonment`_ :
    It is defined as an action where the user open the results but does not
    complete an engagement action, usually unfocusing the urlbar. This also
    happens when the user switches to another window, if the results popup was
    opening.
  - `Impression`_ :
    It is defined as an action where the results had been shown to the user for
    a while. In default, it will be recorded when the same results have been
    shown and 1 sec has elapsed. The interval value can be modified through the
    `browser.urlbar.searchEngagementTelemetry.pauseImpressionIntervalMs`
    preference.

.. _Engagement: https://dictionary.telemetry.mozilla.org/apps/firefox_desktop/metrics/urlbar_engagement
.. _Abandonment: https://dictionary.telemetry.mozilla.org/apps/firefox_desktop/metrics/urlbar_abandonment
.. _Impression: https://dictionary.telemetry.mozilla.org/apps/firefox_desktop/metrics/urlbar_impression


Custom pings for Contextual Services
------------------------------------

Contextual Services currently has two features involving the address bar, top
sites and Firefox Suggest. Top sites telemetry is described below. For Firefox
Suggest, see the :doc:`firefox-suggest-telemetry` document.

Firefox sends the following `custom pings`_ to record impressions and clicks of
the top sites feature.

    .. _custom pings: https://docs.telemetry.mozilla.org/cookbooks/new_ping.html#sending-a-custom-ping

Top Sites Impression
  This records an impression when a sponsored top site is shown.

  - ``context_id``
    A UUID representing this user. Note that it's not client_id, nor can it be
    used to link to a client_id.
  - ``tile_id``
    A unique identifier for the sponsored top site.
  - ``source``
    The browser location where the impression was displayed.
  - ``position``
    The placement of the top site (1-based).
  - ``advertiser``
    The Name of the advertiser.
  - ``reporting_url``
    The reporting URL of the sponsored top site, normally pointing to the ad
    partner's reporting endpoint.
  - ``version``
    Firefox version.
  - ``release_channel``
    Firefox release channel.
  - ``locale``
    User's current locale.

Changelog
  Firefox 108.0
    The impression ping is sent for Pocket sponsored tiles as well. Pocket sponsored tiles have different values for ``advertiser`` and ``reporting_url`` is null. [Bug 1794022_]

  Firefox 87.0
    Introduced. [Non_public_doc_]

.. _Non_public_doc: https://docs.google.com/document/d/1qLb4hUwR8YQj5QnjJtwxQIoDCPLQ6XuAmJPQ6_WmS4E/edit
.. _1794022: https://bugzilla.mozilla.org/show_bug.cgi?id=1794022

Top Sites Click
  This records a click ping when a sponsored top site is clicked by the user.

  - ``context_id``
    A UUID representing this user. Note that it's not client_id, nor can it be
    used to link to a client_id.
  - ``tile_id``
    A unique identifier for the sponsored top site.
  - ``source``
    The browser location where the click was tirggered.
  - ``position``
    The placement of the top site (1-based).
  - ``advertiser``
    The Name of the advertiser.
  - ``reporting_url``
    The reporting URL of the sponsored top site, normally pointing to the ad
    partner's reporting endpoint.
  - ``version``
    Firefox version.
  - ``release_channel``
    Firefox release channel.
  - ``locale``
    User's current locale.

Changelog
  Firefox 108.0
    The click ping is sent for Pocket sponsored tiles as well. Pocket sponsored tiles have different values for ``advertiser`` and ``reporting_url`` is null. [Bug 1794022_]

  Firefox 87.0
    Introduced. [Non_public_doc_]


Other telemetry relevant to the Address Bar
-------------------------------------------

Search Telemetry
  Some of the `search telemetry`_ is also relevant to the address bar.

contextual.services.topsites.*
  These keyed scalars instrument the impressions and clicks for sponsored top
  sites in the urlbar.
  The key is a combination of the source and the placement of the top sites link
  (1-based) such as 'urlbar_1'. For each key, it records the counter of the
  impression or click.
  Note that these scalars are shared with the top sites on the newtab page.

Telemetry Environment
  The following preferences relevant to the address bar are recorded in
  :doc:`telemetry environment data </toolkit/components/telemetry/data/environment>`:

    - ``browser.search.suggest.enabled``: The global toggle for search
      suggestions everywhere in Firefox (search bar, urlbar, etc.). Defaults to
      true.
    - ``browser.urlbar.autoFill``: The global preference for whether autofill in
      the urlbar is enabled. When false, all types of autofill are disabled.
    - ``browser.urlbar.autoFill.adaptiveHistory.enabled``: True if adaptive
      history autofill in the urlbar is enabled.
    - ``browser.urlbar.suggest.searches``: True if search suggestions are
      enabled in the urlbar. Defaults to false.

Firefox Suggest
  Telemetry specific to Firefox Suggest is described in the
  :doc:`firefox-suggest-telemetry` document.

.. _search telemetry: /browser/search/telemetry.html

Event Telemetry
---------------

  .. note::
    This is a legacy event telemetry. For the current telemetry, please see
    `Search Engagement Telemetry`_. These legacy events were disabled by default
    and required enabling through a preference or a Urlbar WebExtension
    experimental API.

.. _Search Engagement Telemetry: #search-engagement-telemetry

The event telemetry is grouped under the ``urlbar`` category.

Event Method
  There are two methods to describe the interaction with the urlbar:

  - ``engagement``
    It is defined as a completed action in urlbar, where a user inserts text
    and executes one of the actions described in the Event Object.
  - ``abandonment``
    It is defined as an action where the user inserts text but does not
    complete an engagement action, usually unfocusing the urlbar. This also
    happens when the user switches to another window, regardless of urlbar
    focus.

Event Value
  This is how the user interaction started

  - ``typed``: The text was typed into the urlbar.
  - ``dropped``: The text was drag and dropped into the urlbar.
  - ``pasted``: The text was pasted into the urlbar.
  - ``topsites``: The user opened the urlbar view without typing, dropping,
    or pasting.
    In these cases, if the urlbar input is showing the URL of the loaded page
    and the user has not modified the input’s content, the urlbar views shows
    the user’s top sites. Otherwise, if the user had modified the input’s
    content, the urlbar view shows results based on what the user has typed.
    To tell whether top sites were shown, it's enough to check whether value is
    ``topsites``. To know whether the user actually picked a top site, check
    check that ``numChars`` == 0. If ``numChars`` > 0, the user initially opened
    top sites, but then they started typing and confirmed a different result.
  - ``returned``: The user abandoned a search, for example by switching to
    another tab/window, or focusing something else, then came back to it
    and continued. We consider a search continued if the user kept at least the
    first char of the original search string.
  - ``restarted``: The user abandoned a search, for example by switching to
    another tab/window, or focusing something else, then came back to it,
    cleared it and then typed a new string.

Event Object
  These describe actions in the urlbar:

  - ``click``
    The user clicked on a result.
  - ``enter``
    The user confirmed a result with Enter.
  - ``drop_go``
    The user dropped text on the input field.
  - ``paste_go``
    The user used Paste and Go feature. It is not the same as paste and Enter.
  - ``blur``
    The user unfocused the urlbar. This is only valid for ``abandonment``.

Event Extra
  This object contains additional information about the interaction.
  Extra is a key-value store, where all the keys and values are strings.

  - ``elapsed``
    Time in milliseconds from the initial interaction to an action.
  - ``numChars``
    Number of input characters the user typed or pasted at the time of
    submission.
  - ``numWords``
    Number of words in the input. The measurement is taken from a trimmed input
    split up by its spaces. This is not a perfect measurement, since it will
    return an incorrect value for languages that do not use spaces or URLs
    containing spaces in its query parameters, for example.
  - ``selType``
    The type of the selected result at the time of submission.
    This is only present for ``engagement`` events.
    It can be one of: ``none``, ``autofill``, ``visiturl``, ``bookmark``,
    ``history``, ``keyword``, ``searchengine``, ``searchsuggestion``,
    ``switchtab``, ``remotetab``, ``extension``, ``oneoff``, ``keywordoffer``,
    ``canonized``, ``tip``, ``tiphelp``, ``formhistory``, ``tabtosearch``,
    ``help``, ``block``, ``quicksuggest``, ``unknown``
    In practice, ``tabtosearch`` should not appear in real event telemetry.
    Opening a tab-to-search result enters search mode and entering search mode
    does not currently mark the end of an engagement. It is noted here for
    completeness. Similarly, ``block`` indicates a result was blocked or deleted
    but should not appear because blocking a result does not end the engagement.
  - ``selIndex``
    Index of the selected result in the urlbar panel, or -1 for no selection.
    There won't be a selection when a one-off button is the only selection, and
    for the ``paste_go`` or ``drop_go`` objects. There may also not be a
    selection if the system was busy and results arrived too late, then we
    directly decide whether to search or visit the given string without having
    a fully built result.
    This is only present for ``engagement`` events.
  - ``provider``
    The name of the result provider for the selected result. Existing values
    are: ``HeuristicFallback``, ``Autofill``, ``Places``,
    ``TokenAliasEngines``, ``SearchSuggestions``, ``UrlbarProviderTopSites``.
    Data from before Firefox 91 will also list ``UnifiedComplete`` as a
    provider. This is equivalent to ``Places``.
    Values can also be defined by `URLBar provider experiments`_.

    .. _URLBar provider experiments: experiments.html#developing-address-bar-extensions