There is a contradiction in the description of the subgroup relationship which I have seen being used to apply what I believe to be incorrect edits.

https://musicbrainz.org/relationship/7802f96b-d995-4ce9-8f70-6366faad758e currently says:

This links a subgroup to the group from which it was created. This relationship type is the functional equivalent of the member of band type for group-group relationships.

Personally, I agree with the wording that says a subgroup is created from a group.  In that case, the second sentence is a contradiction in the following scenario:

• "Group A" collaborates with "Group B" to form a one-off artist "Supergroup".  Although "Group A" and "Group B" are "members" of "Supergroup", it is not the case that "Group A" and "Group B" are created from the supergroup - rather, it is the supergroup that is created from Group A and Group B.

This is actually the very example provided by https://musicbrainz.org/relationship/75c09861-6857-4ec0-9729-84eefde7fc86:

Girlschool (a group) collaborated on Headgirl (another group)

Motörhead (a group) collaborated on Headgirl (another group)

Therefore, I think the second sentence needs to be deleted from https://musicbrainz.org/relationship/7802f96b-d995-4ce9-8f70-6366faad758e, leaving the description as just,

This links a subgroup to the group from which it was created.