Since the deprecation of XUL/XPCOM extensions in favor of WebExtensions, Firefox extensions are restricted to JavaScript APIs for security. VDPP operates within this sandbox, utilizing:

: Look for a numeric badge on the extension icon in your toolbar. This number indicates how many video streams have been captured.

The extension operates through a detection-and-tab-caching system:

This extension distinguishes itself by handling modern streaming protocols that standard downloaders often miss.

in the corner of Firefox, signaling that the "sniffing" technology had successfully identified the video stream. The New Tab

: During the download, the video segments are temporarily stored in your browser's memory. It is critical not to close this tab until the "Save" button appears, or the progress will be lost.