The UI is basically a 1-to-1 copy of an older version:
https://blobbackup.com/images/logs.png
http://bvckup.com/img/shot-6.png
"Good artists create, great artists copy", but that's a bit too close for comfort.
Outside of the main window though, lots of other things are quite different and completely independently arrived at. Bvckup2 doesn't have third party storage support so everything else requires a fundamentally different UI to work in BlobBackup. Look at the settings windows and the menus for example.
Similar to how desktop word processors and browsers all look the same; some patterns just make sense for a specific type of software.
Given that this one uses secondary control labels that are verbatim of Bvckup's, has the same layout and opening screen, and nearly identical look and feel, this is certainly not an independent effort.