It's the OpenSidewalks standard.

https://github.com/OpenSidewalks/OpenSidewalks-Schema/blob/32dad18bb303289f660fd8d26f02f5e301d0a9d1/OpenSidewalks_Mapping_Guide_P1.pdf

If a short footway is not used to divide the curb node from the sidewalk centerline, then the router interprets the user as needing to navigate a curb in order to go around a corner, when this is not the case in reality. This doesn't impact routing for most users, but it is necessary for routing for users with mobility concerns.

As for the naming, in my tests, short enough segments of footway are ignored in TTS routing instructions, so their lack of names hasn't presented a problem. Giving sidewalk segments names at all seems to be a divisive topic (since the sidewalk itself isn't inherently named "Rue Sherbrooke Est," for example, it's merely associated with the street of that name,) but having the names on the main segments has produced good routing directions in all my tests. 