What is this?

[GreG L.]

After a 5 hour trip found this on the floor in front of the door. No idea, some kind of spring loaded stop or retainer.

[Mikendebbie]

Check your table...it might be one of the knobs you pull to extend the table.

[AV Tech]

It's your table slide lock

[Mikendebbie]

Yep...here is a pic of my table...

[GreG L.]

That's it, thanks. I think I saw that only once, never used it. I guess there are worse things that could vibrate loose on a 3,500 mile trip.
Had to be the Mississippi roads.

[Daryles]

BTW, your table top lifts up for storage underneath