Alternatively I thought maybe you needed to have some closed source component from a vendor and could only include it like that.
It's true that vendors are likely to be an area where we have to deal with some things being closed source, though we're not simply accepting that as a given. This is one reason we're writing so much of our own software, and also, poking at the bits that must remain closed: https://oxide.computer/blog/lpc55
Well, nearly anything having to do with wireless is typically blobs :/
Even Nordic has blobby SoftDevices, though you don't have to use them since Apache NimBLE exists (and rubble in Rust though that's only usable for advertising-only for now).
Sounds like I should plan to do that on my own at the moment, but I'll keep it in a github style fork in case y'all's focus moves in that direction.