In bug 1352204 we will be disabling non-MPC extensions by default on Nightly. This bug is to add a new boolean scalar to telemetry indicating whether a given profile has any non-MPC extensions installed. This will serve two purposes: 1. Allow us to quantify how many users were affected by the non-MPC change (more specifically, how many were affected enough to flip the pref back) 2. Allow people studying performance data to optionally filter out data from users who have non-MPC extensions enabled, when it is known that those extensions introduce unwanted noise into performance related metrics.

I think this can get done quickly but a couple of questions: 1. Any objection to adding extensions.allow-non-mpc-extensions to DEFAULT_ENVIRONMENT_PREFS too? 2. I can either add a new boolean property to the "addons" part of the environment indicating whether any non-MPC extensions are installed, or add a multiprocessCompatible property to each individual extension. Any reason to prefer one of those over the other?

> 1. Any objection to adding extensions.allow-non-mpc-extensions to > DEFAULT_ENVIRONMENT_PREFS too? No please do that. > 2. I can either add a new boolean property to the "addons" part of the > environment indicating whether any non-MPC extensions are installed, or add > a multiprocessCompatible property to each individual extension. Any reason > to prefer one of those over the other? I slightly prefer the .multiprocessCompatible property because it's more flexible for measuring other things such as "which MPC=false addons are most popular on channel X".

Comment on attachment 8861125 [details] Bug 1358620 Add telemetry for non-MPC extensions https://reviewboard.mozilla.org/r/133084/#review136302 ::: toolkit/components/telemetry/TelemetryEnvironment.jsm:630 (Diff revision 1) > updateDay: Utils.millisecondsToDays(updateDate.getTime()), > signedState: addon.signedState, > isSystem: addon.isSystem, > isWebExtension: addon.isWebExtension, > + multiprocessCompatible: Boolean(addon.multiprocessCompatible), > }; This needs to be documented in environment.rst also.

Comment on attachment 8861125 [details] Bug 1358620 Add telemetry for non-MPC extensions https://reviewboard.mozilla.org/r/133084/#review136314 code review and data-review=me Please ping somebody on the data team (gfritzsche?) about getting this into the ping schema->derived data sets->longitudinal

Georg, re comment 6, is that something I should just open a new bug for or do you have some other process?

Pushed by aswan@mozilla.com: https://hg.mozilla.org/integration/autoland/rev/4bac91d15349 Add telemetry for non-MPC extensions r=bsmedberg

Mark, can you take a look at what actions are needed per comment 6? This adds to the environment: - an entry to userPrefs - an addon property

I've filed bug 1360174 to add this data to the Longitudinal dataset, and bug 1360177 to add it to Main Summary and downstream Addon-related datasets.