For my purposes, the add-on is great, because it doesn't have a lot of bells and whistles and can be reached more quickly than, for example, Firebug, which always takes up a not inconsiderable part of the browser window.
You can also find the add-on on the Firefox add-on page: https://addons.mozilla.org/de/firefox/addon/quickjava/
Jens has been running the blog since 2012. He appears as Sir Apfelot for his readers and helps them with problems of a technical nature. In his free time he drives electric unicycles, takes photos (preferably with his iPhone, of course), climbs around in the Hessian mountains or hikes with the family. His articles deal with Apple products, news from the world of drones or solutions for current bugs.