tubestation/toolkit/components/glean/docs/preferences.md

Preferences

Test-only Preferences

telemetry.fog.temporary_and_just_for_testing.data_path

This controls the data path Glean is initialized with (nightly only). It is intended for manual testing only. It will be removed once FOG gets a fixed data path. By default it is not set. Change requires restart.

telemetry.fog.test.localhost_port

If set to a value port which is greater than 0, pings will be sent to http://localhost:port instead of https://incoming.telemetry.mozilla.org. Defaults to 0.