The special page that Matt wrote for T132127: Display documentation for notification types configuration on Wikimedia made me realize how weird the notification categories are. This is what I see on my localhost:

System (system): welcome, thank-you-edit
User rights change (user-rights): user-rights
Other (other):
Talk page message (edit-user-talk): edit-user-talk
Edit revert (reverted): reverted
Page link (article-linked): page-linked
Mention (mention): mention
Email from other user (emailuser): emailuser
Flow (flow-discussion): flow-new-topic, flow-post-reply, flow-post-edited, flow-topic-renamed, flow-summary-edited, flow-description-edited, flow-mention, flow-enabled-on-talkpage, flow-topic-resolved
Page review (page-review): pagetriage-mark-as-reviewed, pagetriage-add-maintenance-tag, pagetriage-add-deletion-tag
Thanks (edit-thank): edit-thank, flow-thank

Things I think we should fix:

• flow-mention should be in the Mention category
• flow-enabled-on-talkpage should be in the System category
• User talk-related Flow notifications should be in the Talk page message category (T132426: User don't receive email notifications concerning their Flow talk page when "Talk page message" is on, but "Flow" is off)
  • This is non-trivial to do right now, because these notifications were not implemented as separate types. Instead, Flow's notification types present themselves differently when they're about the user's talk page. Presumably we'd have to split off separate types for user talk.
• We shouldn't have all Flow notifications in one big category, we should split it up. We may not need one per type, but we also shouldn't have a category with nine types in it (seven if we move out flow-mention and flow-enabled-on-talkpage, but I think that's still too many)

@jmatazzoni , @Pginer-WMF , @Quiddity, @Trizek-WMF: Thoughts? Ideas?