@RandomUser
I'll give you one:
https://gitlab.com/stuiterveer-ut-apps/afvaller
to not make anyone angry, I'll add 3 apps in :
pure qml (javascript):
https://github.com/pparent76/PDFjs
c++:
https://gitlab.com/matdahl/jsonedit
rust:
https://gitlab.com/cristodcgomez/parasol
I give no warranty about the beauty of the code for any of these apps that I did not write, it's all in the eye of the beholder anyway.
However, I have only included relatively small apps.
For studying code, it's so much better than trying to study big things like dekko or puremaps (that's not to say that these big things are bad, to the contrary, these are among the best of the best but are not appropriate to learn)
If anyone can contribute small apps demonstrating the use of other languages, I'll be happy to add them to my personal collection. Sadly I don't think that Ada, Cobol, C#, or Malboge are really supported for now.