There is no CLI way, how to delete group from tag.
Metadata Update from @tkopecek: - Issue set to the milestone: 1.14
I've decided to expose only groupListBlock, not groupListRemove as it should cover all needs.
groupListBlock
groupListRemove
PR: #509
Commit a9dc6987 fixes this issue
Commit 6c68b6ab relates to this ticket
This issue has been migrated to Fedora Forge: https://forge.fedoraproject.org/koji/koji/issues/462
Please continue any further discussion there.