I've noticed that the messages wikilambda-functioncall and wikilambda-reference are not documented clearly: their qqq just says "Label for the word function call." and "Label for the word reference.". I'd expect qqq to say also in which context these labels are used.

I tried finding where they are used, and they appear not to be used anywhere in the extension. If I run git grep -P "wikilambda-functioncall[^-]" -- ":(exclude)*.json" and git grep -P "wikilambda-reference" -- ":(exclude)*.json", I find no results. (There are several "wikilambda-functioncall-*" messages, and they are used, but if I exclude them from the grep using [^-], I find nothing.)

They seem to have disappeared from files other than JSON in https://gerrit.wikimedia.org/r/c/mediawiki/extensions/WikiLambda/+/931311/3/resources/ext.wikilambda.edit/Constants.js . (Several other "labels" there used to appear in en.json, but aren't there now.)

If these two messages are actually used as messages, they should greppable and documented more clearly in qqq. If they are not actually used, they should be deleted from i18n/*json and extension.json.