Thanks https://github.com/fantasai, despite multiple reviews, somehow missed that https://www.w3.org/Consortium/Process/Drafts/snapshots/2023-04#groups line: > … and a participant is a member of such a group. This resolves the semantics of the first paragraph of this issue as invalid, leaving only potential editorial confusion from the use of multiple terms for the same thing, which is not a MUSTFIX (issue title adjusted accordingly).

Thanks https://github.com/fantasai, despite multiple reviews, somehow missed that https://www.w3.org/Consortium/Process/Drafts/snapshots/2023-04#groups line:
> … and a participant is a member of such a group.

This resolves the semantics of the first paragraph of this issue as invalid, leaving only potential editorial confusion from the use of multiple terms for the same thing, which is not a MUSTFIX (issue title adjusted accordingly).