I talked about this with @gabriel-wmde and considered this again.

1. We can keep the pills, but use commas as separator, but that would create some technology overhead: A new widget would need to be created
2. We could just separate by comma, use no specific "syntax highlighting" like the pills and give that a try. It make that clear to users, we could show a "separate search words or phrases by comma (,)" if such a field has focus (so we don't need to write it over and over again). If in the test users are like "I get the comma thing, but It confuses me where the terms start and end", we have a good reason that additional syntax highlighting would help. In that case, still, no work would have been wasted.

I would go with 2) because it is efficient and we have good reason to believe it will work, too. That would mean that the acceptance criteria above need to be rewritten. Would that be OK, @Lea_WMDE ?

@Jan_Dittrich, I'm ok, as long as you are confident. Do you feel safe with such a change without any more user testing or would that mean another round of testing before it becomes a beta feature?

@Lea_WMDE: I talked to Gabriel briefly: We can also do create the pills on Comma, BUT we would not display the comma then (as no linebreak does happen on Enter). I think it is too off-standard, so I feel as confident as it could to just go with the commas first.

I do no expect terrible-messy things are likely to happen (because we don't do any "tricks" in the UI here), so I am fine without user tests, but I might try to test internally to check.