I'm having the same issue with RabbitVCS as this post: Rabbit VCS on Ubuntu 18.04 - not showing menu in Nautilus. However, I've followed the accepted answer and the comments, and I still do not get the RabbitVCS context menu.
UPDATE: Below are the results of the commands from the other post that I followed. Also, if it makes a difference, I'm running inside VirtualBox.
~$ aptitude search rabbitvcs
p rabbitvcs-cli - Command line interface for RabbitVCS
i A rabbitvcs-core - Easy version control
p rabbitvcs-gedit - Gedit extension for RabbitVCS
i rabbitvcs-nautilus - Nautilus extension for RabbitVCS
~$ ll ~/.local/share/nautilus-python/extensions/
total 52
drwxr-xr-x 2 alager alager 4096 Jan 28 14:20 ./
drwxr-xr-x 3 alager alager 4096 Jan 28 14:20 ../
-rw-r--r-- 1 alager alager 24082 Jan 28 14:20 RabbitVCS.py
-rw-r--r-- 1 alager alager 20384 Jan 28 14:20 RabbitVCS.pyc
Update2:
~$ python /usr/share/nautilus-python/extensions/RabbitVCS.py
/usr/share/nautilus-python/extensions/RabbitVCS.py:63: PyGIWarning: Nautilus was imported without specifying a version first. Use gi.require_version('Nautilus', '3.0') before import to ensure that the right version gets loaded.
from gi.repository import Nautilus, GObject, Gtk, GdkPixbuf