In ID web editor there's a "relations" section underneath the tags section. It's a good thing to watch out for if you're editing existing roads - especially if you're splitting segments, deleting segments, or adding new segments, since you could accidentally cause a gap in the relation (which could represent for example a bus route) or cause incorrect ordering of relation segments for things where the order of the relation members matter. I typically try to avoid making any unnecessary changes to anything that's in a relation besides tag updates and repositioning alignment, both because each relation type has its own conventions that I don't want to dive into learning and also because editing relations in ID instead of josm can be hard and laggy with huge relations.

And it looks like someone else found the default speed limits for comaps, I had no idea that was a thing probably because I rarely notice roads without speed limit tags.