This limitation for example caused that Fedora could only contain one major version of every package (by policy)

This is a bit misleading. Sure we can have multiple versions of packages as long as we name them differently -- arguably, then it is no longer the same package, but nevertheless, I'd remove this sentence entirely.

@churchyard removed the sentence.

@ppisar finished all the changes i wanted to make. Please if you have time go through it so we can can catch mistakes or errors. Thanks

s/package name of is not/package name is not/

"A modular repository can still provide non-modular repositories..." is awkward. A repository cannot contain a repository. I recommend instead:

A modular repository can still provide non-modular RPM packages which are not part of a module.

s/a RPM/an RPM/

s/a RPM/an RPM/

s/a RPM/an RPM/

Fix the next sentence: s/Module repository/Modular repository/ to mach the title.

Use a module name we already have in Fedora: s/postgres/postgresql/.

s/yaml/YAML/g Unless you speak about a file name extension, use the capitalized form. It's an abbreviation. Similar to RPM.

s/When running/Running/

From the listing it's not obvious that modulemd-build package is non-modular. You are describing facts which cannot be interfered from the listing. It will perplex the users. You would need to open the YAML file. I think this is not helpful.

Unicode has vertical ellipsis "⋮". Consider using that instead of three lines. Those lines make the example too long.

You missed 9th item "filter".

s/context configuration or context/a context configuration or a context/ It's difficult to parse it without articles.

s/file/package/g.

s/file/package/g.

A typo: depe ndency

I finished the review. It's a huge improvement. Thanks.

Thanks for the review @ppisar and @churchyard! Rebased and updated according to your points. I will merge this for now. When some other mistakes/errors pop-up please make an issue.