I downloaded the fork of the engine (4.21) https://github.com/simul/UnrealEngine/tree/4.21 . Build worked without error but I can’t find the plugin in the editor.
Then I downloaded and installed the “Win64 Binaries for UE Source Build” form My Profile - Simul Rebuild the engine and still no plugin.
After doing I notice that in my Engine/plugin/TrueSkyPlugin folder I only have 2 folders, “Source” and “Shaderbin”