G disabledClasses

Usage
This variable can for example be set by a map. In the worldspawn, add the key "disabledclasses" and set its value to a comma delimited list of classes (e.g. "level1upg,level4") that is to be unavailable in the evolve menu. Binds cannot override this.

With this in mind, see also G_disabledEquipment and G_disabledBuildables.