What's the status of the Cancellation proposal?

I'm not familiar with the TC39 proposal process. Can anyone explain to me what's the status of the Cancellation proposal? It advanced to stage 1 but the proposed design in stage 0 was archived, saying "TC39 has decided that Cancellation is something that must be considered as part of the core specification." Wasn't TC39 already part of the core specification? And how can it got moved to stage 1 without having a "general shape of a solution and illustrative examples of usage"? Are they awaiting for solution suggestions or are there pending challenges need to be solved?

I think this is the most recent reference from the meeting notes: notes/dec-01.md at 7a03ba62d42e7dc4d22f26883098d74d64bc13c4 · tc39/notes · GitHub talking about Host hook-based cancellation · Issue #31 · tc39/proposal-cancellation · GitHub