Install Please give us some info about these 2 new EL8 variables?

Yup those variables are for the linked Mold linker as alternative to linux default GNU linker and current Centmin Mod Nginx and PHP-FPM used Gold linker. It's meant to in theory speed up overall Nginx and PHP-FPM compilations though in real life hasn't been much difference from my tests. But that could be due to Mold linker being heavily beneficial in multi-threaded CPU systems (more CPU cores the better).