APC Works (Adequate Programming Code) was a source code project by Brian Haley (aka Bounty Hunter) between 2000-2001. It included changes to vision modes, changes to the number of flares (as well as their color), and adds firebombs as a weapon. The predator energy rate is tweaked. The map Hanger2Beta, which included a reskin of the marine dropship, was also a part of this project.
Another part of the project was a program called LCP, which was released in v.2.0 and v.2.1 forms. I'm not sure what the point of this program is, but it might have been a program for users to choose between different modded aspects that they wanted to include in their game. A combination skin and sound mod was also released. Several download links survive and some screenshots show a few of the modded aspects.