Comparing to your changeset from the same day, I found way/311837949 which matches your decription. This used to have a painted cycleway on the sidewalk, before the cyclelanes in the road was built. And they are now going to revert this, remove the cyclelanes from the road, and back onto a new segregated cycleway on the "sidewalk". https://miljopakken.no/prosjekter/falkenborgvegen

It would help a lot if you indicated which way you are talking about.

The changeset you are commenting on is mainly about updating along the signposted cycle routes in Trondheim. It is also 4 years old, and stuff has changed. It's a large changeset from several days of GPX tracks.

Also while I always advocated for not highway=cycleway on general sidewalks, if it's signposted as a cycleway, it is a cycleway even if it otherwise looks like a sidewalk.

Note that 4 years ago, footway=sidewalk was not yet widely used, and we were still discussing the *=designated tag.