Every sevice on this domain with a login has it's own account management, and stores data like your name and email when you log in. You can partially edit these accounts to add a porfile picture or another email, and you can usually also delete that sevice-specific account.
Most services use the central SSO system under https://auth.libre.moe for authorization and identity purposes, meaning some facts like your username, primary email and user ID are stored and managed centrally. Changing them in the SSO management portal will also distribute these changes upon login into the respective service.
The central SSO system does not feature a delete button, as the deletion would not affect your sub-accounts on each sevice. Deletion should therefore be manually requested.
Not all systems on here are/should be linked to your SSO, meaning you have a seperate identity/login for these.
Accounts are free and provide certain free services, of course limited to fair use. If your accounts stores data in it, this data still resides on this infrastructure and is included with backups, incurring a small cost. Thus, when accounts become inactive but store a noticeable amount of data, they will get deactivated and later deleted.
If you notice an old account is not accessible anymore, please contact me so we can try to restore it.