Anybody know what this hole is on the rear passenger side door sill of a 08 Honda Fit Sport? Is there a trim part that goes there?

 

That looks like a hole that was drilled by Krown for their anti-rust spray treatment. The cap that they put on must have fell off. I don't recall if my 07 Base has a hole or not, but to the best of my memory I don't think having a hole there is stock.

 

Access hole for paintless dent removal

 

Speed holes :P

 

Definitely looks to be a PDR hole, just find a rubber grommet to cover it up but put some touch up paint on the edges first to prevent rust.