I'm assuming they mean SDL ports of DOS games. SDL is actually one of the most stable libraries that a native game can use. They make breaking changes to the API once every 10-15 years, and they write a compatibility layer that implements the previous version's API using the current version's API as a backend. This has happened twice so far, so there's an SDL 1.2 implementation that uses SDL 2 and an SDL 2 implementation that uses SDL 3. These can be chained together, so for example you can run an SDL 1.2 game from the early 2000s on a modern Linux system and it'll have native Wayland and Pipewire support thanks to using SDL 3 behind the scenes.