> What does "behind" actually mean, though?

In this case, reading the link you're replying under, it's being able to mount a disk formatted with a popular filesystem. The alternative here is waiting for a human to type this relatively "solved" problem, as a procedural requirement, more than anything.

So, it can easily mean "things won't work in this OS". But, that's to be expected with FreeBSD, for legitimately good (from the perspective of FreeBSD) reasons.

As one example I can think of, there are a ton of devices that only work on Windows (or Windows and MacOS). The audio interface I have is one example: its "official drivers" are Windows and MacOS only. I know that someone is trying to make Linux drivers for it, using LLMs, because if there's one thing LLMs are very good at, it's RE and figuring out how hardware works. One of my other friends made an accessible equivalent to the Razer app for his Razer headphones because the official app is complete shit.