BSPSource

BSPSource is a VMEX-based map decompiler for the Source engine. It converts BSP format files back into VMF format maps that can be loaded into Hammer. Support has been extended to newer Source games, such as Counter-Strike: Global Offensive, Left 4 Dead 2, and Portal 2. Most of the bugs found in the latest release of VMEX have been fixed, and new features have been added.

Some of its features are:

• Extracting embedded content (protected maps may cause errors)

• BSP analysis

• Support for processing multiple files at once

• Convenient BSP file Drag & Drop

• Much more!

Note: Decompiling maps may not always result in accurate builds. Some properties, such as keyvalues and texture settings, may not match those of the original map. A common example (bug) are misplaced areaportals.

Source: https://developer.valvesoftware.com/wiki/BSPSource

Reference: https://github.com/ata4/bspsrc