If you downloading Eclipse ECF as a ZIP file, the plugins folder in the ZIP contains pack200 compressed JAR files. The pack200 compressed files ends with *.pack.gz. The ECF ZIP distribution contains the same content like a normal Eclipse P2 update site.
If you like to use Eclipse Equinix ECF bundles without P2 or Eclipse you must unpack the pack200 OSGi bundels. For that eclipse provides a tool called "org.eclipse.equinox.p2.jarprocessor". Here a small bash script to show how to extract the OSGi bundles from the pack200 files.