I installed a few themes from gnome-look.org
The site uses a special URL scheme. The URL handler comes in a package named
ocs-url. Here are the instructions for installing the URL handler on linux-apps.com.
However, the installation method described on this site has an issue: it marks the dependencies as manually installed.
Therefore I recommend the following method instead.
My method will ensure that, when you uninstall ocs-url, its dependencies will be automatically uninstalled as well.
First download the
ocs-url Debian package, then (filename and directory name might differ):
sudo dpkg -i ocs-url_3.1.0-0ubuntu1_amd64.deb
sudo apt-get install --fix-broken
Once this is done, all you have to do is click on install links on gnome-look.org and them click "OK" and the themes will be installed in
Restart the Tweaks tool and your new themes should be available.
Tested on Debian.