This is a browser extension that pulls YouTube videos off watch pages, Shorts, and embeds so you can save MP4 or WebM files locally. It hooks into YouTube's InnerTube API to grab available qualities from 144p to 4K, handles the messy adaptive streaming stuff automatically, and merges separate audio and video streams when needed. You get three free downloads to test it, then it's gated behind email login for unlimited use. The extension adds an in-page download button directly on the YouTube player and works across Chrome, Firefox, Edge, and a few others. Good for archiving reference material or keeping offline copies of stuff you already have browser access to.
npx skills add https://github.com/serpdownloaders/skills --skill youtube-downloader