https://webkit.org/licensing-webkit/
WebKit is part LGPL, and part BSD.
So I think from purely a licensing point of view, they are probably not in violation. Provided that the way they are linking the LGPL-licensed code is compatible with the LGPL.
But like the other commenter said, I too would not run any web browser that was not fully open source, like this Orion browser.
If they are forking Webkit, like they say, doesn't that require they distribute the source to their fork? Even if they don't have to distribute the browser linking to it?
Or do I not understand the obligations of LGPL?