Thanks, that mostly clarifies it.
ref:LV:addr is a tag that community has decided to match addresses to the official cadaster data.
As addresses are not assigned by LP, I'd assume their identifiers are post-factum, mostly for their own purposes.
Also not sure whether those are properly licensed as open data, thus they might be best discarded for now.

This seems like a great topic for the Zulip community chat, we might continue there :)