There is a custom compound property 'abc' on DesignRevision which referes property xyz on PartRevision through "representation_for" relation.
If object class name ("Design Revision") and property name ("abc") are input, is it possible to get relation (representation_for), Object class (PartRevision) and source property (xyz) as output ?
I'm not aware of any API that can give you this directly.
The compound property definitions are stored in ImanCompoundPropDef objects.
There are properties display_type_name and compound_prop_name that give you the type and property where the compound is defined.
source_type_name and source_prop_name give you the target at the end of the compound.
object_hierarchy is a string array that gives you the segments.
You would need to query the objects and parse the segments yourself.