I just got reminded that my Hexcalc Challenge/BugBouty remained unclaimed in 2022:

https://github.com/v-p-b/hexcalc#challenge

Can anyone solve this in 2023? :)
GitHub - v-p-b/hexcalc: DIY calculator with a hexadecimal keypad

DIY calculator with a hexadecimal keypad. Contribute to v-p-b/hexcalc development by creating an account on GitHub.

GitHub
Convincing me to merge a PR with a #bugdoor is also fair game ;)
Akkoma