Use of GitHub's code owners feature
The handbook should provide some help with regard the use of GitHub's code owners feature.
The use of GitHub's code owner feature is consistent with the EDP (provided there is a well defined open, transparent, and meritocratic criteria for designating code owners). I'm pretty sure that our infrastructure is indifferent to code owner and it should "just work", but if you have trouble with it, open a help desk issue to get help from the IT team.
Note that the code owners feature doesn't override roles; that is, individuals listed in a CODEOWNERS file also need to be assigned a role with necessary privileges to merge pull requests.