I'm 99% certain that Akai are using whatever drivers are available with the Linux kernel, as-is, because there's just too much variety to test against. To get an idea, here's a
May 2021 picture from Linux driver developer Geoffrey Bennet of a set of Focusrite Scarlett boxes he had for testing the Linux device drivers. And that's not even all, there are more models - by June 2021 he had
nine different models for testing.
Nine devices to get just the Focusrite Scarlett support working! They all have potentially subtly different behavior, and need tweaks in the driver to get things to work for all models, and maybe also depending on whatever USB stuff is on the host computer side. AFAIK, this effort was not supported by Focusrite, it's volunteer work and donations. That's what it looks like to me. But now everybody can benefit from it, even Akai.
Oh yeah, I probably need to point out that those Focusrite boxes are supposedly "class-compliant". Yet you need model-specific tweaks. The class-compliance is a joke. What it means in practice is that Focusrite tested that the boxes work with Macs and iPads, nothing more. That's where the "Mac class-compliant" oxymoron comes from.
