I have been looking for the code where the EvalRotation() function is implemented, but I can’t find it. I have looked on GitHub and in the documentation, but all the files I find don’t have the code. They always call functions from files I can’t find.
As Ian pointed out, the recommended approach to locate the implementation of any function is to trace OpenFHE in debug mode. EvalRotate’s implementation can be found here. It gets the corresponding evaluation/rotation key and calls EvalAtIndex whose implementation can be found here. You can carry on by stepping into OpenFHE in debug mode.