Here's a patch some hokey shell stuff to put build information in camnotes.txt, which is also incorporated into the readme.txt
The output is like
*** Build Information ***
CHDK for sx510hs fw:100d compatible fw:100c 100a PID:12919
build:1.5.0-5240 date:Sat, 10 Aug 2019 20:02:56 -0700
*** Camera specific notes ***
I'll probably check this in if there are no objections.
For cameras that are built form another platform (currently only sx270/sx275 built from sx280 I think) it lists the target camera, like sx275. IMO this is the better thing to do, since the PIDs are different, making FI2 files not cross compatible.
If you build a copied sub (e.g. sx510hs 100c in the above example) the real firmware is still listed first, followed by the compatible ones.