Tesla is full of open source software, including the Linux kernel. They probably are GPL violators though.

https://sfconservancy.org/blog/2018/may/18/tesla-incomplete-... https://sfconservancy.org/blog/2019/oct/30/calling-all-tesla... https://sfconservancy.org/blog/2023/dec/21/tesla-no-source-c...

See also this interesting slide deck about the GPLv3 and cars, I expect that regulations would mean you could not drive cars with modified software (similar to what happens with solar inverters):

https://events19.linuxfoundation.org/wp-content/uploads/2017...