While the getTag method will display the tag extra data, if I am not missing anything, the createTag method dosn't support to set extra data for a tag. Except that, seems editTag* methods should be fixed, too.
editTag2 supports it (though as you pointed out, does not say so in the docstring). The old editTag call isn't really used anymore, but I guess we probably extend it too.
PR
Commit dcf8f52e relates to this ticket
Resolved by PR#174
@mikem changed the status to Fixed
Fixed
Metadata Update from @tkopecek: - Issue set to the milestone: 1.11
This issue has been migrated to Fedora Forge: https://forge.fedoraproject.org/koji/koji/issues/166
Please continue any further discussion there.