What does warning “Mapping architecture arm64 to x86_64” mean?

Question

After migrating my framework to Xcode 10 beta (10L176w) I started to get warnings like:

Mapping architecture arm64 to x86_64. Ensure that this target\

Answer 1

I was able to silence these warnings by changing my Valid Architectures setting to $(ARCHS_STANDARD) which matches my Architectures setting as well.

Oddly, this displayed as armv7 arm64 (in comparison to the default setting of armv7 armv7s arm64), but setting it to that value manually still caused the warnings. Not sure what the significance of that is, but I haven't noticed any problems in my testing yet.