Recently changed pads and the rotor. Anti rattle clip was there and the new-ish rotor was nice and flat.
The movement is the rest of the caliper itself relative to the mounting bracket that attaches to the lower outer fork tube. It's probably normal movement (slight), but seems like it
could be the source of the rattle/thunk sound I hear on rougher roads. Which is pretty much all of the Denver metropolitan and suburban area
. The sound isn't a buzzing or fast rattle. More like a single noise on more pronounced bumps.