These might be too far off the beaten track for you, being non-standard languages with full game library systems, but Mark Sibly's Monkey2 (discontinued for lack of support) is a complex transpiler project written in a very read-friendly language:
https://github.com/blitz-research/monkey2/tree/develop/src/m...
... and one of his previous languages, BlitzMax, is continued by others today as BlitzMaxNG, and it uses a frequently-updated transpiler based off the former/similar Monkey language:
https://github.com/bmx-ng/bcc
Again, easy to read, and the principles are the same for almost any language.
Downloadable distros:
https://blitzresearch.itch.io/monkey2
https://blitzmax.org/
Targets include Windows x86/64, Mac, Linux, Android and HTML5... among others!