The new version (for Firefox Quantum) doesn't work for me. It downloads a corrupted file that will not run in players. Also, when opening its Options, the following error message appears:

"File not found." The message is longer, but Firefox prohibits copying it.

During download, no progress bar is shown.

There is no way to submit a problem report.

This version seems not to have been tested!

Firefox 57.0 (64-bit)
Video Downloader version unknown