PxrCryptomatte is supplied as a Sample Filter plugin. As such the output for Cryptomatte is stored as a separate EXR file from your beauty or denoise outputs. Please note an OpenEXR is required to store the values correctly. See here for how to attach sample filters and how to combine sample filters. 

Layers

• Name

• Path - like name but instances show up separately

• material

• Attribute
  • user:__objectid - based on OBJ node grouping 
    
    
    
  • user:cryptomatte - parameter in renderman spare parameters
    
  
  
  • user:myatttr - primitive attribute on packed geometry only. Note on unpacked geometry, primitive attributes are renderman primvars not attributes and so cannot be read by pxrcryptomatte
    
    
    
  • any attribute can we specified such as visibility:camera, Ri:Matte, etc

...