It doesn't work with Firefox now, only Chrome.

Don't waste your time; it's been reported on GitHub with no response from the dev.
What a shame. I donate to FOSS projects that don't suck.

В версию ФайерФокс 52.9 его не загрузить - отстой!!!!

Works on my machine™

I found the add-on setup process with JS to be too complicated and wasn't working. I really just needed a quick/easy solution to manage downloads with multiple threads and ability to resume, etc.

doesn't work

It doesn't work on Linux.

Не работает.

Great addon. Jdownloader is the best. Can you please add easy video downloading from YouTube? Currently you have to copy link for it to be added to linkgrabber