Because some websites were unfairly blocked from accessing its services, Chromium-based browser Vivaldi modified the user agent string (UA string) from the newly released Vivaldi 2.10 to mimic Chrome to circumvent the blocking. UA String is the data that is sent when the browser establishes its initial connection to the Web site, including data such as the browser type, the rendering engine, and the operating system.
For example, the UA string for the Windows version of Firefox is “Mozilla/5.0″ (Windows NT 10.0; Win64; x64; rv:71.0) Gecko/20100101 Firefox/71.0”. UA string began in the 1990s, and websites can use this data to adjust performance and functionality, or to block outdated browsers. But many websites today use UA string to block users, partly because they are reluctant to handle browser-specific bugs, partly because of the red tape, and Microsoft and Google do so to dominate the market against competitors. Vivaldi is based on Chromium, which, like the Chrome base code, says it’s blocked mainly because of competitors.