View source for Telemetry/Quirks

=== Histograms of general interest ===

Oftentimes, Telemetry users need "denominators" for a % calculation:

* To get the # of Firefox sessions in a data set or from telemetry.mozilla.org, just count the # of entries in any once-per session histogram: SIMPLE_MEASURES_FIRSTPAINT (startup time measurement), STARTUP_CRASH_DETECTED, E10S_AUTOSTART (whether e10s is enabled, recorded at startup), etc
* To get the # of pages visited: look at TOP_LEVEL_CONTENT_DOCUMENTS_DESTROYED or CONTENT_DOCUMENTS_DESTROYED or FX_PAGE_LOAD_MS
* To get an idea of "overall responsiveness" during a session, look at BHR reports or FX_REFRESH_DRIVER_FRAME_DELAY_MS

=== Ping generation ===
* ''environment-change'' pings are throttled, any environment changes are ignored for 5min after one change was triggered
** this means that e.g. some "short" changes may never show up

=== Data consistency ===
* profiles might switch channels, e.g. switching between nightly & release
* profiles might switch versions/builds in either direction, e.g. downgrading to previous versions on the same channel