Flashgot was one of my essential addons. It is gone. I have been waiting for months for a replacement to come up, but in vain. It is a mystery to me how Mozilla made all those wonderful extensions unusable. I shall now switch to Opera or Chrom if I find a replacement for Flashgot there. Good bye, Firefox!
I can’t recommend that addon anymore.
It seems that the original has been discontinued from addons mozilla com, and that the latest upload was made by a scammer. Avoid!