jOpenSim Usage Groups
Here you find an overview of groups in your grid. Clicking on the group name will show you the group charter.
Unlike SL, there is no automated group deletion if no members join within a certain time, so you can manually delete these mistaken groups here. Maybe also some groups charter does not meet your grid rules.
If GetTexture is enabled, yu will be able to see the choosen group insignia here directly coming from your grid
From viewer side, it is not possible for the last owner to leave a group. But obviously a group with an owner not wanting to be is a lost group. This why jOpenSim provides the possibility for users to leave a group from their inworld account even if the user is the last user. Such a leaderless group can be repaired by you with this button (in case there are any other members left, otherwise only deletion is the logical step).