I have found this link: https://launchpad.net/ubuntu/+source/int...code/+changelog
In ubuntu os speack of changelog for many microcode version.
Whats think?

I see those often, I think it's change logs of build/programs people are making, where they insert and or update to different microcodes as the builds progress or new microcodes become available.

I've find this too: https://tracker.debian.org/pkg/intel-microcode/news/?page=3
More package where explicated changing for microcodes modules, example speack of errata, speack for meltdown etc.

Yes, that's similar to ones I was talking about seeing before too. They put microcodes into OS more often that Windows, well used to be more often than windows (now spectre/meltdown force windows to do similar too)
Change logs with that kind of info are usually posted on the Intel download page too, in change log txt or other datasheet on same download area for that release.