I was porting a model from revelations into ape but then when adding one of the images I notices it was suffixed with _m while others like color images and ao images are _c and _o.

What type of image is _m? I just need to know what kind of images to make it and where to put it in the material in ape.

EDIT:
Also, is there any way to know what texture goes into what material? The textures don't have the same names as the materials so I don't really know where to put them.

Select the material in maya to see which image it uses

_m is a mask map - also used as emissive