Think you are missing the point a little here, PDMLink is not a customization tool or application development tool for Windchill, but is the PDM element of Windchill.
Or in other words:
PDMLink = Windchill
ProjectLink= Windchill
MPMLink = Windchill
they just cover different areas of PLM, the group name of which from PTC is Windchill.
Cheers