File Extensions beginning with the letter 'Y'

Extension	Description	Format	MIME Type
Y	(1) YACC grammar
Y	(2) Archive; Amiga YABBA
YAL	Arts & Letters clipart library
YG1	Database Index; Also YG2, YG3...
YG0	Database Index; Paradox secondary index; see XG0
YBK	Microsoft Encarta Yearbook
YUV	Picture; YUV4.1.1
YM	Sound; Compressed Binary Chip-Music
YEL	Yellow color separation. BLA (Black) CYA (Cyan), MAG (Magenta) Adobe Color Separation