There are no VRML plugins in Ubuntu (my current distro) at present. So I downloaded a copy of FreeWrl and installed that. After working out how to actually get Firefox to take notice of it
I found that the plugin’s menus draw behind its drawing area and that those worlds I could get it to draw it didn’t seem to place the camera in properly.
I then downloaded the source for OpenVrml. After several hours of building and the same plugin installation dance as FreeWrl I found that it just jammed on the worlds I looked at.
I wish both projects well, and I’m sure they work well with the worlds they are designed to render, but they are a dead loss for just getting on with browsing web 3D. I’ll see if I can dig out some of my old worlds to try them on.
Crosbie (in the comments) recommends OpenCroquet, which I am downloading. And I am installing the Microsoft anti-Free Software timebomb that is Mono in order to run OpenSim and try Free Software Second Life networking.
But I still just want a VRML browser plugin that just works.