Filtering OpenStreetMap by username

[opk12]

I am an OpenStreetMap mapper and use Qlever as a search engine. How can I filter the features that were ever touched / last touched / never touched by a user? An OSM user has a numeric unique identifier (which can not change) and a case-sensitive username (which the user and the vandalism moderators can change). I've already searched the examples on the OSM wiki and in the QLever GUI.

This example from Sophox has PREFIX osmm: <https://www.openstreetmap.org/meta/> then you do osmm:user "user_name"; but it does not seem to work in QLever.

Another question: if a mapper wants to learn about missing features, which one (if any) would you suggest to link into the OSM Wiki's article on QLever: the issue QLever missing features or unexpected behavior or the wiki Current deviations from the SPARQL 1.1 standard? I don't know which one is still relevant today / up-to-date.