This task is about implementing the changes necessary to ensure people are being bucketed in the Edit Check A/B test (T342930) as expected.
**Bucketing requirements**
* Bucketing should include both registered and unregistered users
* Everyone who is accessing a desktop or mobile main namespace page (NS:0) at any of the participating wikis, logged in and logged out, should have a 50% chance of being included/bucketed into the A/B test's control or test group
* Bucketing should be done on a per-Wikipedia basis. 50% of people within a given wiki should be placed within the control group; 50% should be bucketed in the test group
* People should remain in the same group for the duration of the test.
* Testing should be done across all desktop skins where available
**Instrumentation-Related Requirements**
* Within the A/B test, we are able to distinguish all events logged for the control group and the test group.
* An `anonymous_user_token` is applied to these events so we can track distinct unregistered users in addition to distinct registered users.
* We are able to track if/when someone in the test group adjusts any of the edit check-related preferences (if available)
**Participating wikis**
Defined in T345298 (still being finalized)