Actually, I was referring to Netsurf in general, not a specific implementation (I assume the rendering engine is the same for all forks and versions?). 
no, its not. netsurf has different frontends for different platforms. chris has programmed a native reaction one for os4 which is included upstream and therefore officially supported.
the amiga one depends on sdl framebuffer which is considered to be only a fallback implementation since it has limitations in comparison. afaik the autor of amiga 68k port is not as experienced a coder to provide a proper native renderer and therefore cant contibute upstream in order th have it officially maintained, but it seems he is overcoming the limitation of his port one by one, even though some might consider it hackery. just lately i read that the browser window is now dynamically resizeable, did not try it yet though myself.
