Unable to answer "What is the width of the opening here?" – Gate – https://osm.org/node/277082240 via StreetComplete 63.0:

We have 3 doors, each with 2 wings. Each wing is easily 1m wide. However: I've never seen them open, and there are no opening times listed. I'd say it's fine to say the smallest opening here is 1m, but it's unclear to me if that is ever useful for pathfinding.