They did provide the apidoc in a zip file:
plugins\org.eclipse.platform.doc.isv_3.0.0\doc.zip
and in that zip file
reference\api
Found it while looking around for JFace source code, which
is under
plugins\org.eclipse.platform.source_3.0.0
Don't know who comes up that idea hiding it inside a directory
which has 103 directories...
Rejoice!
