The gen-yoo-wine HD shop manual (as well as anotherguy) says they are 10mm 12 point. This is them:
I DID find a cheap 10mm socket - part of the plastic boxed metric socket set I bought in 1969 with my paperboy money. It's as toothless as a 20 year old cat.
I saw the spline sockets and wondered if they'd do better than a 12 point - the Internets seem to disagree if they are wonderful or worse than this:
Anotherguy, where do I apply the heat gun - the body of the caliper? I was thinking of heating the head of the bolt with my small butane torch, then waiting and hitting the head with a shot of freon spray to shrink it.