Source vote vs Destination vote vs Head vote accuracy

what's the difference between Src / Dst / Head accuracy?
more importantly, how do they each affect the validator reward?

I think that
- "head accuracy" measures the % of attestations which vote correctly on the previous block, and has significant effect on the validator reward
- while Src / Dst are about the sync committee and who's included in it, and doesn't affect the reward the same way

if that's the case, I would expect "Correctness" to be much more affect by head accuracy than by src/dst

would love to get some concrete explanations on these 🙏