Bug #668842 landed locale to telemetry metadata, but that got dropped at some point 'til then. I dove a bit into the history, and I suspect it'll turn out to be related to bug 668392 adding another-but-different copy of getMetadata.

Notably bug 685880 removed the getLocale() bit actually being hooked up. I came across this because I was curious to see how many people use a particular build of ours, and that turned out to be hard, as blocklist pings show general.useragent.locale localized pref value, and telemetry would show active locale code, if it worked.

Nathan, please cleanup the mess I created :(

Autoland Patchset: Patches: 603107 Branch: mozilla-central => try Destination: http://hg.mozilla.org/try/pushloghtml?changeset=726c85f0d365 Try run started, revision 726c85f0d365. To cancel or monitor the job, see: https://tbpl.mozilla.org/?tree=Try&rev=726c85f0d365

Try run for 726c85f0d365 is complete. Detailed breakdown of the results available here: https://tbpl.mozilla.org/?tree=Try&rev=726c85f0d365 Results (out of 28 total builds): exception: 2 success: 23 warnings: 2 failure: 1 Builds (or logs if builds failed) available at: http://ftp.mozilla.org/pub/mozilla.org/firefox/try-builds/autolanduser@mozilla.com-726c85f0d365