Microchip Library for applications provides demo code for USB - "CDC basic demo" & "CDC device serial emulator". I found all of them are related to microchip - USB communication, but what are the main difference between them.
Functionally both implement the USB communications device class with various Microchip devices. A diff of the two projects reveals the makefiles and most source files are identical. The cdc_basic project appears to add build support for more devices.