It completely breaks YouTube and other sites, changing the original format that can be downloaded to “TS” format. On YouTube, it becomes impossible to download videos in “MP4” format. Since I disabled this extension, everything has returned to normal. I ended up installing IDM (Internet Download Manager) Premium, which is faster and integrates with Firefox. I do not recommend VDH, especially the paid version, which is completely useless since they removed the file conversion feature that existed before.
