Good eye! Those scripts are not used anymore, they were early prototypes. You can see the comments in the PR here: https://github.com/ublue-os/bluefin/pull/606#issue-195447621...
Literally everything is running scripts directly from the internet, without any version pinning or check summing.
There is no way to run the same build twice and have any confidence that the result was the same.
https://github.com/ublue-os/bluefin/blob/41bdf294c20a3903f4a...