Error message: "The worklist can include up to 7000 pages. Remove some pages before saving."
✅ Verified. A worklist with 7,000 pages (6,999 on one wiki and 1 on another) saves. With 7,001 pages, the save is refused with "The worklist can include up to 7,000 pages. Remove some pages before saving." The number is formatted for the user's language.
✅ The limit counts pages across all wikis in the worklist, not per wiki.

✅ Confirmed. With the job runner stopped, I edited the worklist page to add one local page and one page on another wiki. The CampaignEventsUpdateWorklistPagesSecondaryStore job was still queued, but both new pages were already in the response, with the right link classes ("new" for the red link, "external" for the other wiki).

The design and AC don't match. The patch implements the design correctly, but the AC says "TextArea placeholder reads 'One title per line'".

The action attribute gets added to the outer <div>, not the <form>, which is invalid and does not work. It causes a regression of I3fd518.

$1 was supposed to be the error details

TYSM @JFernandez-WMF I'll adjust the grid accordingly

~~ @VPuffetMichel This is the one we talked about, @Daimona said there is a Codex-PHP update coming that will change this work dramatically, so it's on hold for a short time. ~~

I have a number of questions that are not captured here:

✅ Given that someone toggles on private registration when registering for an event,
They should see updated explanatory text, which includes the following added sentence: "Your username will be publicly visible if you contribute to a public event worklist."

✅ If a worklist page is created for an event that is not a contribution event, then the worklist should not be associated with the event.
✅ If a contribution event has an associated worklist but its event type is changed to be non-contribution, then the worklist should be disassociated
✅ If the event page of a non-contribution event already has a /Worklist subpage, and the event type is changed to be a contribution type, then the worklist should be associated

✅ Given I am on Special:MyEvents
Then, the label for the search field is Search (case sensitive) (changed from Search)
✅ Given I am on Special:AllEvents
Then, the label for the search field is Search keyword (case sensitive) (changed from Search keyword)

QA notes.

✅ verified

Given I am allowed to enable registrations
And I am viewing a page in the Event: namespace
And that page does not have an associated event
Then I should see the "enable registration" header if the content model of the page is wikitext

The dataset is here. It was not possible to get a live list of organiser data, so this will not work for future data and will need to be rebuilt.