Nextcloud Backup creates multiple files

[FullyBorked]

I haven't updated just yet.  I do rely on these backups and I'm confused a bit reading all this.  Can someone clarify what's going on here?  So, each backup file isn't a full backup?  For example with a restore we'd need a full and a diff?  I clean up backup files on the Nextcloud side, want to make sure I understand this so I don't blow out a full backup and bork up my ability to restore if needed. 

Or am I misunderstanding and this just creates a full backup on ANY change?  Along with just a goofy naming convention.