e.g. https://meta.wikimedia.org/wiki/Special:Contributions/~2024-21718

Currently page displays: (1) this user is not registered; (2) this user is globally blocked

What I expect in: User account "xxx" is not registered in this wiki. There is a global account for xxx. You can <view global account information for it>. (with a link to Special:CentralAuth/xxx)

Note what I propose is neither specific to Meta nor to temporary accounts (e.g. https://www.wikidata.org/wiki/Special:Contributions/Adegoke_bro may also have such message), but Meta is more important since such contribution pages are linked from logs and recent changes.