However, these positives are . The extension was removed from both the Firefox and Chrome official stores for policy violations, third‑party security monitors have flagged it as having a “high” or “very high” risk likelihood of containing malware, and it requires privacy‑invasive permissions like access to all browser tabs and all website data.
It wasn’t on the official Mozilla Add-ons store. That was the first red flag, but in the world of digital archiving, red flags are often just traffic lights telling you to slow down, not stop. The GitHub page was sparse. The user icon was a generic gradient. The description was written in broken English: "Download any video from web. High speed. Mpmux technology."
Limitations
The "Video Downloader Professional Plus - Mpmux" for Firefox was a technically impressive tool that mastered the complex challenge of downloading streaming video from the web. Its standout features—seamless HLS handling and multi-threaded downloads—made it a powerful choice for many. However, its removal from the official Firefox Add-ons Store due to significant security and privacy concerns cannot be overlooked. For your ongoing safety and a reliable browsing experience, it is best to uninstall this extension and transition to one of the well-established, actively maintained alternatives recommended in this guide.
Detects $1080p, 4K, and higher resolution streams. Video Downloader Professional Plus - Mpmux Firefox
Always check the website’s terms of service and your local laws before downloading.
: Because it merges files in your browser tab, downloading very large videos (over 2GB) can sometimes cause the browser tab to crash if you have low RAM. Legal Note However, these positives are
Some versions allow users to add videos to a "personal list" for later playback or use Google Chromecast to cast MP4 files directly to a television. Important Considerations and Limitations
If you are a Firefox user, several high-quality alternatives are available: That was the first red flag, but in