Comment 3 for bug 1716656

Looking at the file list for the entangle package:

   https://packages.ubuntu.com/eoan/amd64/entangle/filelist

We can see that the plugin code simply isn't included at all.

Only the gschema files in /usr/share have been installed

The code and registration metadata from /usr/lib(64) are missing.

A proper install for a plugin install would have 4 files:

/usr/lib64/entangle/plugins/shooter/shooter.plugin
/usr/lib64/entangle/plugins/shooter/shooter.py
/usr/share/entangle/plugins/shooter/schemas/gschemas.compiled
/usr/share/entangle/plugins/shooter/schemas/org.entangle-photo.plugins.shooter.gschema.xml

NB, /usr/lib64 might be elsewhere on Ubuntu