> Libreboot is a fork of Coreboot
They've always called themselves a "Coreboot distro", not a fork. From the homepage: "In the same way that Debian is a GNU+Linux distribution, libreboot is a coreboot distribution."[0]
That was a lot bigger deal when libreboot first started, because at the time Coreboot wasn't doing their own releases, so doing release engineering and such around Coreboot was a lot more of a value-add.
> Libreboot … refuses to include things such as CPU microcode.
That is false since the libreboot+osboot merger. Osboot was a fork of libreboot that had a more lax binary blob policy; they merged back together last month[1], taking osboot's more lax policy[2], which does block out some binary blobs from upstream Coreboot, but allows important blobs such as CPU microcode.
> Because the FSF
I'd be hesitant to say that libreboot does anything because of the FSF; libreboot and the FSF have had a... tumultuous relationship, for both technical/policy reasons, and personal reasons. Libreboot's policy page[2] has a big section about disagreements with the FSF's policy. It's more fair to say that libreboot does things because of Leah Rowe's position on things, which will tend to align with the position of FSF supporters, but not necessarily.
[0]: https://libreboot.org/
[1]: https://libreboot.org/news/merge.html
[2]: https://libreboot.org/news/policy.html