There may be hundreds of distros but there is only one kernel developer, the
Linux Foundation under Linus Torvalds. The Linux kernel is where most things
happen. The Linux kernel is monolithic and proprietary blobs have been part
of it for a long time. Some distros such as Debian have begun stripping
proprietary blobs from the kernel, but the practise is not widespread. It
would be easy to add an asterisk to exclude distros that follow this
practise. May not work with Debian, etc.