Unfortunately, this extension doesn't actually block the link (at least not in the same way ad blockers do).

It just displays a pop-up window informing you that the page is blocked.
In devtools->network, I still see the page's traffic after the blocking message.

P.S. If this is helpful, the server can also be installed on the windows version of Python.
However, you need to add DATABASE_PATH = path to the .db database to your environment variables.

Doesn't work

At first it appeared to do nothing. It does actually work. Big issue is you have to type or copy\paste offending url. It would be nice to have a "block current\this site button under submenu.