Finds objects missing from the OSM DB. As a start, it finds missing streets and house numbers based on a reference list.
The latest version is v6.0, released on 2020-05-22. See the release notes.
It works by fetching the street and house number list for a relation (area), then suggesting what possibly missing objects are a good idea to survey.
You can see this in action at public instances: vmiklos.hu, vasony.hu.