0CC is the file extension added in 0CC-FamiTracker version 0.3.14.0 to distinguish between vanilla FamiTracker modules and those using features exclusive to 0CC-FamiTracker.

The 0CC format itself is an extension of the FTM format used by official builds of FamiTracker. If a given 0CC module does not use any 0CC-FamiTracker features, it may be opened in an official FamiTracker build by selecting "All files (*.*)" in the "Open File" dialog (the same way ".ftm.bak" files can be opened—although official FamiTracker is never able to produce backup files even if the option is enabled).