On a car side window, what is the part called that goes into the tracks, and feels like felt?

The Devil2019-08-03T20:47:04Z

Those are weatherstrip seals. The window regulator raises and lowers the glass.

thebax20062019-08-03T11:57:52Z

Run channel. Usually it's a bad window regulator if the widow comes out of the run channels.

Jay P2019-08-03T09:40:23Z

'Window run channel' or 'window channel' for short.

L.N.2019-08-03T03:45:09Z

They are actually called window felts.
https://www.youtube.com/watch?v=jvn4bA9c0-Q