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+Debugging
+=========
+
+For other debugging resources, see also: Remote project [wiki]
+
+Increasing the logging verbosity
+--------------------------------
+
+To increase the internal logging verbosity you can use the
+`remote.log.level` [preference].
+
+If you use mach to start Firefox:
+
+	./mach run --setpref "remote.log.level=Trace" --remote-debugging-port
+
+By default, long log lines are truncated. To print long lines in full, you
+can set `remote.log.truncate` to false.
+
+Enabling logging of emitted events
+----------------------------------
+
+To dump events produced by EventEmitter,
+including CDP events produced by the remote agent,
+you can use the `toolkit.dump.emit` [preference]:
+
+  ./mach run --setpref "toolkit.dump.emit=true" --remote-debuggiing-port
+
+
+Logging observer notifications
+------------------------------
+
+[System observer notifications] are used extensively throughout the
+code and it can sometimes be useful to log these to see what is
+available and when they are fired.
+
+The `MOZ_LOG` environment variable controls the C++ logs and takes
+the name of the subsystem along with a verbosity setting.  See
+[prlog.h] for more details.
+
+	MOZ_LOG=ObserverService:5
+
+You can optionally redirect logs away from stdout to a file:
+
+	MOZ_LOG_FILE=service.log
+
+This enables `LogLevel::Debug` level information and places all
+output in the file service.log in your current working directory.
+
+
+[preference]: ./Prefs.html
+[System observer notifications]: https://developer.mozilla.org/en-US/docs/Archive/Add-ons/Overlay_Extensions/XUL_School/Observer_Notifications
+[prlog.h]: https://searchfox.org/mozilla-central/source/nsprpub/pr/include/prlog.h
+[wiki]: https://wiki.mozilla.org/Remote/Developer_Resources