The license typically works across different browsers (Chrome, Firefox, Edge) as long as you use the same email for registration. Free Alternatives to Video DownloadHelper
Around version 8, the developers began requiring a license for certain advanced features (watermark removal, removing download frequency limits, companion app access). The extension always remained free to install and use for basic functionality. The change was designed to generate revenue for continued development of the project.
A command-line tool that is widely considered the best video downloader in existence. It is open-source, free, and supports thousands of sites without watermarks.