"The file customlearning.sppkg has been checked out by i:0#.f|membership|****@.org.uk on 6/16/2020 9:42 AM"
Asterisks denote personal info. The user left the organisation and had their AD profile deleted months ago. The file can't be deleted or overwritten in the library. When I check the files which aren't currently checked in on library settings, the section is empty
I have Global Admin priveleges and I own the library where the apps are stored/deployed
I have had a chat with a Sharepoint Engineer from Microsoft who said they would get back to me, but they pointed me in the direction of GitHub for help, who in turn pointed me in the direction of TechCommunity for help.