Juanito,
I resubmitted the caja and engrampa extensions. This time they are built from source, using latest stable release.
As before, the extensions are DE/WM-agnostic.
Please post them at your convenience.
P.S. Building was moderately to severely painful, so I submitted for x86_64 only. If users want to build for other architectures, my build notes are attached. Hopefully having notes will take the edge off.