How easy is it to find a copy of the Codex Astartes in the 41st millennium?

I know that it’s the super best tactical and strategic guide of all time for Space Marines but in all the books I’ve read I don’t think I’ve seen a single non Space Marine refer to it.

As a holy book it’s surely nowhere near as common as the Lectitio Divinatus, but do temples to the Emperor keep a copy of it? Is it part of standard training at the Schola Progenium? Would Imperial Guard commanders have a copy? Or is it exclusively a Space Marine thing?

If a chapter of Space Marines lose their copy does mean they have to go to some planet sized library to get another copy, or does every marine in the chapter have their own travel sized version?