The company doesn't tell websites it's actually Vivaldi anymore, in order to cut down on sites either misbehaving or rejecting the browser as unsupported.
In a blog post a out the new Vivaldi 29, the company said: "From this update onwards, users will be able to browse smoothly all those websites that claim to be incompatible with Vivaldi."
A video revealed browser incompatibilities with things like Google Docs, WhatsApp, Google search and Netflix, as well as issues with Twitch, Shopify, Microsoft Teams and more.
Although the web is an open platform, Google is powerful and influential, which means new or less common browsers can struggle to get a foothold with websites rejecting them.
To get around this isssue, Vivaldi's user agent approach sees the browser - which is built using the same open-source Chromium software as Chrome's foundation - pretending to be its more widely used alternative.
The same programme is also used for the likes of Opera, Samsung Internet and Microsoft's latest version of Edge.