About [[Toolserver:Getwikiapi-label-wikiids/en]]

What does "wiki identifiers" mean here? Is it interwiki prefixes, language codes, or something else?

Probably database names (like enwiki, enwikt, etc.).

OK, translated it keeping this in consideration.

Actually, it's all of those. See also:

https://toolserver.org/~krinkle/getWikiAPI/

it supports databasenames, language codes, hostnames and urls and some others as well

PS: I've updated Toolserver:Getwikiapi-label-wikiids/qqq

Thanks for updating the doc. The translation I did should be valid in all these cases.