The add-on is offered by the official 'Adaware' site, so it should be genuine.
Zero ratings can mislead or puzzle people but this is the premier of the protection addon.
However, only after good amount of testing can one evaluate it's effectiveness against the likes.
Yeah, I couldn't find it either. I'm not sure if it even works without Adaware's paid solutions because its free AV doesn't include any web blocking and it doesn't push this extension as a way to introduce web blocking like Avira does with its free AV.