WRAP is a wrapper mainly used for palettes and images. The first subblock in a WRAP block is always the OFFS block, which holds the offsets to each block that the wrapper... wraps. :)

"WRAP"	dword	Block identifier
dwSize	dword	Size in bytes (BE)
blOFFS	block	OFFS block
followed by subblocks (e.g. APAL, SMAP etc.)