We have just discovered (June 3rd, 2021) that the plugins from Plugin Alliance are not implemented for Apple Silicon and therefore they will only run under Rosetta.
Gig Performer 4 does run natively under Apple Silicon and consequently, if you run the Universal version of Gig Performer 4 on a Mac M1 or other ARM based Mac, the VST and VST3 plugins from Plugin Alliance will NOT be available.
You will therefore need to run either the non-universal (Intel CPU only) version of Gig Performer 4, or you will need to check the “Open with Rosetta” option (found through the Get Info menu for Gig Performer 4).
In both these cases, Gig Performer 4 will run under Rosetta, Apple’s technology for executing programs compiled for Intel on their new ARM based computers.
This is a non-optimal solution as you no longer benefit from the increased speed of the M1 processor.
For instructions on how to work around this problem, see this KB article.
For more information about the Plugin Alliance version of Gig Performer, please see this KB article.