The link above points to a brower extension but your browser probably will not trust it and install it as active.
To install it, download the file and then go to your browser's extensions page (for example, in Edge, go to edge://extensions/), enable "Developer mode", and then drag and drop the downloaded file onto the extensions page. It will still probably fail.
You can change the extension to zip and extract contents. Then use the Developer mode Load unpacked function. However, this is now in developer mode and can't be used without a nag every 2 weeks.
It is possible to make changes to the registry to have this extension load. This location assumes 64 bit edge.
[HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Microsoft\Edge\Extensions\kgoffmcbppiamidpenebcglfnaknnkfn]
"update_url"="https://deathking.com/deathblock/update.xml"
[HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Edge\ExtensionInstallForcelist]
"1"="kgoffmcbppiamidpenebcglfnaknnkfn;https://deathking.com/deathblock/update.xml"
zipped registry entries - requires admin rights to import:
deathblock-reg-install.zip
If you have these entries now the extension is managed by organization. To remove the extension you have to delete the entries. Trying to add the extension by drag and drop will fail if these entries are present.
In Developer mode press Update to force an update or initial install. Then close and open Edge.
You can turn off Developer Mode once the extension is updated.
Or, if you Loaded this extension from unpacked it will have a different id than if it was updated using the registry entries and the registry entries will not matter. But in that case you must stay in Developer mode.
If you have an extension icon right of the URL bar on Edge, look for the DeathBlock extension popup button. You can add URLs to block by entering them in the input field and clicking "Add". Blocked URLs will appear in the list below, where you can remove them by clicking the "Remove" button next to each URL.
Format the exclude url like: *://threatdefender.info/*