Well, depends on what you consider a Linux distro, there are many Android ROMs that are closed in a similar way, including those from phone manufacturers, where

Well, depends on what you consider a Linux distro, there are many Android ROMs that are closed in a similar way, including those from phone manufacturers, where kernel sources are released but nothing else, there definitely existed before Remix OS. Does Android really qualify as a Linux distro? Does a Linux distro need a GNU system behind it? Because that's missing here, no glibc, no coreutils, etc. This is why some people have been insisting on calling it GNU/Linux all along, it can create ambiguity in situations like this. Linux is after all, just a kernel.