More mystery parts in mysterious places..

I removed my passenger side door panel to work on removing a door ding and found this loose piece of what looks like window channel just laying there inside the door? No winder Im getting rust dripping out of the water drains.

Good news is it was only this piece of whatever that was rusting. I removed a handfull of decayed metal from inside the door. More good news is, this is like 2lbs dead weight removed.

I'll try to get some pics. I compared the piece to the cars stock parts and can't find a match. Did some factory worker just throw some random part into my door?

Update: I took a better look and indeed, this piece came from the inside of the door. Doesn't look like it's really needed. It guided the window glass from the lock rod and latch mechanism.. Window operates as usual.

Seems 2 brackets that held it in place just rotted away.

Winter chemicals must be corrosive as hell..

Either that or my car was involved in a flood before I bought it(New)