Rated 5 out of 5 stars

I installed the 3.2 version, and when I go on Help and troubleshooting page, the page in the top part has got some lines on the black background, is it normal?

This review is for a previous version of the add-on (3.1.5). 

yes it is. It s a background image which is repeating. It s like the one you have on this website. I did it to make like a reminder, because Mozilla is using those strips on its different websites. So I found nice to make it, because they created this software and I wanted to add a little something they use often in their graphic identity.