Fuses not documented in header file?

[apakSeO]

Why is there little to no documentation or reference as to what the fuses listed in the device-specific header file actually do? For reference I am referring to device PIC18F46J50, and using the latest version 5.065 of CCS.

For example:

Microchip's config bits are named
EC ECPLL HS HSPLL INTOSC INTOSCO INTOSCPLL INTOSCPLLO

the "O" at the end of the fuse means CLKO out on RA6

Whereas CCS's fuses are named
EC ECPLL HS HSPLL INTRC INTRC_IO INTRC_PLL INTRC_PLL_IO

I don't know what the "IO" at the end of the fuse name means. Does it mean "O" as in MC's fuse names? Does it mean IO as in GPIO?

(1) Why the difference in naming here? To me, using "INTRC" in the fuse suggests that the INTRC 31kHz low-power oscillator is used. Is it? Or does "INTRC" mean the Internal Oscillator block in general?

This is confusing to a new user.

(2) What are all the other fuses doing? Where does a new user find the documentation for all this? In MPLAB, the Configuration bits utility as well as the code output generator explicitly state what each fuse or #pragma _CONFIG statement does. Is there an equivalent in CCS?

[Ttelmah]

fuses.txt with the compiler.

Cross reference this with the data sheet.

For the INTRC_IO for example, this is using the internal RC oscillator, with the OSC pins programmed for normal I/O.