Source is a 3D game engine developed by Valve. It debuted as the successor to GoldSrc with Half-Life: Source in June 2004, followed by Counter-Strike: Source and Half-Life 2 later that year. Source does not have a concise version numbering scheme; instead, it was released in incremental versions
Source code is based on TF2 2018 leak. Don't use it for commercial purposes.
This project is using waf buildsystem. If you have waf-related questions look https://waf.io/book