Zircon Beta Release #1 (source code) file
Zircon Beta is DarkPlaces Beta with all Zircon enhancements rewritten from the ground up and all DarkPlaces Beta bugs encountered were resolved (except a single Q3 shader issue for tcmod scale). Zircon Beta has an optional mouse driven menu, ALT-ENTER...
Darkplaces Mark Arcane Dimensions Zircon Enginea Darkplaces Markv Project Mod For Quake Ircon Beta Release 1 Source Code Evelopment Tools
Source: moddb.com