You're looking for information on uTorrent Web and its license key file, specifically in a portable context.
If you’re looking for a portable, legal torrent client without a paid license, here’s a safe alternative: utorrent web license key file portable
µTorrent (uTorrent) Web | uTWeb is the #1 Web Torrent Client You're looking for information on uTorrent Web and
The Portable Connection: If you are using a portable version, you must manually place this license file into the same folder as the executable for the "Pro" features to stay active as you move between computers. uTorrent Web Free vs. Pro Features not the browser-based uTorrent Web
What is uTorrent Web?
Portable Setup
: Pro features and license key activations are primarily designed for uTorrent Classic , not the browser-based uTorrent Web