progandy

Newer versions should have a replacable waste tank, but the tank does have a chip with serial number.

You can read the raw text https://raw.githubusercontent.com/dessalines/essays/master/why_not_signal.md

Maybe you can register a custom protocol and have your own script outside of flatpak that runs firefox. Then use an xdg-open command that prefixes the custom protocol.

There seems to be a receiver available using some tricks https://github.com/rgerganov/shanocast

Currently there is support for a network connection over thunderbolt you can use as a basis. If you want to send other data without network encapsulation, you'll need to write a kernel module for that.

https://www.kernel.org/doc/html/latest/admin-guide/thunderbolt.html#networking-over-thunderbolt-cable
https://christian.kellner.me/2018/05/24/thunderbolt-networking-on-linux/

I'm not sure how well maintained it is, but porteus-kiosk might ve a very good fit for this use case..

No need for a systemd switch. It should work with a dedicated "portal" browser that bypasses the global dns and has a built-in resolver using the dns from dhcp.