Deletion of groups is a generally desired feature we’d like to support in Gerrit. However, there seem to be two major behaviors/modes depending on host admin/owner preferences: 1) Remove a group without keeping a Git ref to it to reduce the number of Git refs on the Gerrit server. 2) Remove a group but keep its complete audit and add an audit entry for the group deletion.
In core Gerrit, we can’t implement 1) without offering 2) by default as existing host admins/owners might rely on core Gerrit’s audit for groups to keep track of all modifications. Enabling traceless group deletion without explicit consent from these persons would likely result in negative surprises.
Implementing 2) is more effort, though, and even more so if want to offer 1) and 2) both inside of core Gerrit. The proposer of the design wishes to support just 1). Hence, we recommend to implement 1) in a plugin. Before that plugin can become a core plugin in the future, it needs to also support 2).