For heavy Tezfiles users, browser extensions might be limiting because they are still bound by browser stability. A standalone portable downloader is superior because it handles the "fetching" process independently.
For advanced users, the most reliable portable tool is a scriptable one. yt-dlp (a youtube-dl fork) is open-source, portable, and supports Tezfiles. tezfiles video downloader chrome portable
From a legal standpoint, the situation is murky but leans toward violation of Terms of Service (ToS). TezFiles explicitly prohibits automated downloading or the use of third-party tools to accelerate or bypass its queue systems. While simply watching a video stream is permitted, systematically extracting and saving the raw file constitutes a breach of contract. Furthermore, if the video in question is copyrighted material (e.g., a leaked movie or a premium tutorial), the user may be infringing on copyright law, regardless of the portable nature of the browser. The "portable" argument—that one isn't installing anything permanently—holds no legal weight; circumvention is circumvention, whether executed from an SSD or a USB stick. For heavy Tezfiles users, browser extensions might be