This is a file format, not a battle format. Despite the article's implications, there is currently no battle format to which Composer 669 modules can be entered.
Information about the 669 format
The 669 format, also known as the former pc tracker format; consist of sampled tracked music up to 8 channels created by Tran [a.k.a. Tomasz Pytel] of Renaissance on 1992, this format is more limited than the Extended 669 Format implemented in 1994 by Jason Nunn on his Unis 669 tracker.
This vanilla version of the 669 format may have the next header on its first 2 bytes on the module: if
Restrictions on submitting a 669 module
The max size of each sample/instrument must not surpass 1 MByte.
They file must be 128 patterns long at most, with a maximum of 64 rows each one.
The samples must not exceed 22 kHZ.
Effects used for the 669 format
Axx - Portamento up
Bxx - Portamento down
Cxx - Port to note
Dxx - Frequency adjust
Exx - Frequency vibrato
Note: if you set any of those effects with a value of 00, all the effects in that row may be cancelled and the notes that comes next may be played normally
Fxx - Set tempo