Split from parent per @tgr.
[ ] Drop flagging features
[ ] Drop having multiple tiers of review
[x] Drop tier3 (pristine) support – {41d295479e16e5f8fac08368970f0e75cc045710}
[x] Drop tier2 (quality) support – {04ffb5f56f2331138f2463584aacbb702e8d243e}
[ ] Clean-up now there's only one tier
[x] Drop having multiple dimensions of review ("tone", "style", etc.)
[x] Drop "tone" and "style" dimensions – {ddb91cf8b29a894450fe3657dca7153be2797859}
[x] Support only one dimension – {3fe0bacc5bb328a676ba7f1ae623bff982a8cba9}
[x] Drop ability to have pages immune from review – {0fe4ed9a6842b04324d7525447f2c80855c5dd74}
[x] Drop ability to show the version of templates/files that the page used when reviewed – {e4ff4779203d4ec44cdadcfa33f6d634bee1a7f1}
[ ] …
[ ] Drop UX features
[] Special pages:
[x] ProblemChanges – {8d8b3822d3ac9d126f69eb0ea39741b3d6ff9849}
[x] ReviewedPages – {7de102e939d5df33e5b80c504ca838c192b717bf}
[x] ReviewedVersions – {552aaf00394bc3117c8668811ae93838ee23fd5a} (and API equivalent, {dc93e33eb3a73091e5794a31f1125d7a3b0acb03})
[x] AdvancedReviewLog (aka QualityOversight) – {9aed5fdd91f143934aa95ecda9ddfd067471786a}
[x] Drop ability to choose which user groups get shown unreviewed versions by default – {50ffcdf7ca938a976fa7ae40158ef9c6d38dd6db}
[x] Drop background image on non-low profile wikis when a page has a pending edit you're not seeing – {889ee09d2e9109debe857baf00e078e7279595db}
[x] Drop hidden message on non-simple UI wikis when viewing an old stable revision as a a reviewer – {889ee09d2e9109debe857baf00e078e7279595db}
[x] {T285608}
[ ] …
[ ] Drop extension hooks
[x] Drop FlaggedRevsFRGenericSubmitFormReady hook – {e894afbca50be0dea4bd96a7118769a4a657f4e1}
[ ] Drop FlaggedRevsRevisionReviewFormAfterDoSubmit Hook – {I0d73aa07ad247ca37318ff0251a003484739a25c}
[ ] …
[] Merge user rights