We actually know the full grammar for these files: it is documented at
<http://help.eclipse.org/kepler/index.jsp?topic=%2Forg.eclipse.platform.doc.isv%2Freference%2Fmisc%2Fplugin_manifest.html>.
We ought to be able to extract that DTD into a file and give each
"plugin.xml" a "<!DOCTYPE plugin SYSTEM ...>" declaration referencing
it. Unfortunately, that leads to a new warning: "External entity
resolution is not supported by PDE." So a stub declaration is the
best we can do. Fortunately, Eclipse's structured editor seems to
preserve these once we add them by hand.
Ben Liblit
Manu Sridharan
sjfink