Considering the text from the task description that says Should it be removed?, I think it is clear that the guided tour is no longer needed.

I will create a patch to remove it as part of T361044.

Change #1027200 had a related patch set uploaded (by Dreamy Jazz; author: Dreamy Jazz):

[mediawiki/extensions/WikimediaMessages@master] [WIP] Remove Watchlist and RecentChanges guided tours

https://gerrit.wikimedia.org/r/1027200

The tour's purpose was to announce the filters to experienced users when they were introduced. Everyone was supposed to see them already did see them, so it is safe to remove them at this point. I approved the merging patch and moving the task to Growth QA.

Also filled T364269: Drop user properties related to RC tours for dropping the rows.

Thanks @Dreamy_Jazz!

Change #1027200 merged by jenkins-bot:

[mediawiki/extensions/WikimediaMessages@master] Remove Watchlist and RecentChanges guided tours

https://gerrit.wikimedia.org/r/1027200

Change #1027571 had a related patch set uploaded (by Urbanecm; author: Dreamy Jazz):

[mediawiki/extensions/WikimediaMessages@wmf/1.43.0-wmf.3] Backport several WikimediaMessages patches

https://gerrit.wikimedia.org/r/1027571

Might be a good idea to note in user-notice, just in case.

Change #1027571 merged by jenkins-bot:

[mediawiki/extensions/WikimediaMessages@wmf/1.43.0-wmf.3] Backport several WikimediaMessages patches

https://gerrit.wikimedia.org/r/1027571

Mentioned in SAL (#wikimedia-operations) [2024-05-06T12:25:42Z] <urbanecm@deploy1002> Started scap: Backport for [[gerrit:1027237|iglwiki: Enable GrowthExperiments (T364130)]], [[gerrit:1027571|Backport several WikimediaMessages patches (T217451 T362538 T364213 T315774 T364269)]]

Mentioned in SAL (#wikimedia-operations) [2024-05-06T12:45:38Z] <urbanecm@deploy1002> urbanecm: Backport for [[gerrit:1027237|iglwiki: Enable GrowthExperiments (T364130)]], [[gerrit:1027571|Backport several WikimediaMessages patches (T217451 T362538 T364213 T315774 T364269)]] synced to the testservers (https://wikitech.wikimedia.org/wiki/Mwdebug)

Mentioned in SAL (#wikimedia-operations) [2024-05-06T12:51:54Z] <urbanecm@deploy1002> Started scap: Backport for [[gerrit:1027237|iglwiki: Enable GrowthExperiments (T364130)]], [[gerrit:1027571|Backport several WikimediaMessages patches (T217451 T362538 T364213 T315774 T364269)]]

Mentioned in SAL (#wikimedia-operations) [2024-05-06T12:56:55Z] <urbanecm@deploy1002> urbanecm: Backport for [[gerrit:1027237|iglwiki: Enable GrowthExperiments (T364130)]], [[gerrit:1027571|Backport several WikimediaMessages patches (T217451 T362538 T364213 T315774 T364269)]] synced to the testservers (https://wikitech.wikimedia.org/wiki/Mwdebug)

Mentioned in SAL (#wikimedia-operations) [2024-05-06T13:15:55Z] <urbanecm@deploy1002> Finished scap: Backport for [[gerrit:1027237|iglwiki: Enable GrowthExperiments (T364130)]], [[gerrit:1027571|Backport several WikimediaMessages patches (T217451 T362538 T364213 T315774 T364269)]] (duration: 24m 01s)

Checked in wmf.3 - works as expected.

Much thanks for the cleanup!
Re: user-notice - Do you have any suggested wording for the entry in the next edition? E.g. I'm unsure how many projects this change affects, and if it's just 1 or 2 wikis then it might not need/warrant a Tech News entry. -- If it does affect many wikis, then Drafts welcome, here or in the next edition itself. :)
My best-guess would be something like this, but I suspect some nuance(s) are missing:

The old Guided Tour for the "New Filters for Edit Review" feature has been removed.

@Quiddity The summary is this:

1. In 2017, the Collaborations team implemented notices for the then-new RC changes filters (happened in T159010). The notices were set to display only for then-registered users (they did not display to newly registered users, because for them, the features weren't new, but standard).
2. Even though several years passed since the filters introduction, there are still users that are seeing them semi-regularly (cross-wiki users, as the filters display once per wiki, and users returning from a really long wikibreak). There will likely never be a point where everyone saw the tours everywhere.
3. Since the notices are now likely to be mostly annoying, rather than giving any benefits (the RC filters are hardly new at this point), and since it puts undue expectations on both maintenance and databases, it was decided to remove it.

The change impacts all wikis (the description mentions Catalan, but that's because Volker likely did not visit Catalan Wikipedia between 2017 and filling this task, not because the change is specific to Catalan Wikipedia), but it impacts relatively few users (mostly xwiki users, see above).

I believe it's worthy announcing it via User-notice, for two reasons: (a) informing users who were seeing the notices why that is no longer a case, (b) for the (unlikely, I'd say) case someone depended on those notices showing. That being said, I'm unsure how to summarize what I wrote above into the sentence or two format the Tech News expect :). Maybe this provides enough information for you @Quiddity to be able to help with that?

That helps a lot, thanks! (Both for historical posterity, and for this Tech News entry!) I'll still keep it short, but I've added it to Tech News as...

The old Guided Tour for the "New Filters for Edit Review" feature has been removed. It was created in 2017 to show people with older accounts how the interface had changed, and has now been seen by most of the intended people.

Will the now-unnecessary preferences be cleaned up? Except for the users who would still see the notices, all users (including those who have already seen them and those who registered in the past seven years) have two to four rows in the user_properties database table, which is a lot of data. (If it hasn’t been removed, it would be a perfect candidate for $wgConditionalUserOptions, introduced in T321527.) Maybe not right now, in case the WikimediaMessages patch is reverted for any reason, but rather soonish.

I think they already were, see T364269.

Should have looked at the parent tasks; I’ve read the description and the comments, only skipping the information in between… Thanks for pointing that out! The twice 20M+ rows are impressive!

In T217451#9787805, @Tacsipacsi wrote:

[...] If it hasn’t been removed, it would be a perfect candidate for $wgConditionalUserOptions, introduced in T321527. [...]

In this case, they were directly dropped w/o using conditional defaults, as this is a feature removal (the properties are no longer recognized, so there is no need to keep them at all, in any form).

In T217451#9787986, @Tacsipacsi wrote:

Should have looked at the parent tasks; I’ve read the description and the comments, only skipping the information in between… Thanks for pointing that out! The twice 20M+ rows are impressive!

Actually four times! It was ~20M of rows per property per wiki for both loginwiki and metawiki (which are the two wikis you always have an account at, thanks to wgCentralAuthAutoCreateWikis), so about 80M in total (plus a couple of millions on other wikis).