Plasma 6 - Cannot import selected script. Package is not considered valid

Trying to install from https://www.pling.com/p/1833846/ does nothing.
Trying to download from https://www.pling.com/p/1833846/ and Install from File in System Settings > KWin Scripts returns "Cannot import selected script. Package is not considered valid".
Trying to follow the instructions in the README of this repository doesn't seem to have any effect.

Plasma: 6.0.1
KDE Frameworks: 6.0.0
Qt: 6.6.2