Websurf: GNUStep web browser based on Netsurf
vcs.vera-visions.com
vcs.vera-visions.com
What the link is basically saying is that the authors considered none of these to be a good basis for further development, and that's why NetSurf was started.
Of the browsers I've listed, I don't recall any of them having source code available, but Browse may have been part of the RISC OS source code that was released. Most of the browsers were commercial, closed-source products.
This is a port of C based Netsurf ( https://www.netsurf-browser.org/ ) whose modular core allows it to be ported to other toolkits. According to the Netsuf website there are frontends for Amiga, Atari, BeOS, Framebuffer, GTK, RiscOS, and even Windows. Debian contains a GTK+ and a framebuffer variant of it in its repositories.
Websurf is thus not a new application written from the gound up in Objective-C but rather a port of Netsurf to the GNUstep GUI framework.