Thanks for asking about this one, Moin!
You’re absolutely right, empty strings are hidden by default in Crowdin. It looks like I can update our string syncing bot to make them visible, however.
Good point Gerhard, the purpose of this is a bit confusing. Here’s a PR where I’m looking at providing additional context for each keyword entry:
I’m not sure how we can add keywords for every site setting in English that aren’t mostly redundant, however. Settings search already does a simple match against any substring of the setting name (eg, searching for “avatar” will also show “gravatar” settings), so there aren’t many settings that could use additional manually defined keywords.