Did any publicly evidence appear officially or accidentally on the internet that Apple is working on such a project (for Microsoft the situation is known)? I am just a kind of person who prefers strongly to look at the evidence instead of rumors, speculations and hopes.
Sure, but some of this can be learned from monitoring LLVM patches and discussion groups (or attending the usual conferences). It's difficult (or impossible) to keep secrets like this from their underlying communities.
Apple has three (iOS, tvOS, watchOS) of their four platforms on ARM, so LLVM patches related to OSX on ARM could probably be plausibly disguised as patches related to these platforms.
Apple did make some noise about getting rid of support for 32 bit binaries. Reading between the lines this could be because intel owns many patents related to x86. 64 bits is less of an IP nightmare because AMD created x86-64, not intel.
Did any publicly evidence appear officially or accidentally on the internet that Apple is working on such a project (for Microsoft the situation is known)? I am just a kind of person who prefers strongly to look at the evidence instead of rumors, speculations and hopes.