- Linux
- GrapheneOS
- OpenWRT
- webservers / the internet (nginx, databases, storage, networking, ...)
- Mull / Librewolf
- Nextcloud (contacts / calendar sync ...)
- an email server and client
- Matrix chat
- LG WebOS on my TV
- Home Assistant
- lots of user applications
There isn't much important proprietary software in this apartment except maybe for the firmware of the dishwasher / microwave, washing machine and additionally whatever software runs in an old car.