I started making a new modern browser for use on System 6. I named it Browsy. Right now it is just the chrome of a browser, and doesn't actually render pages or make network requests.
It is written in C and builds in Apple's MPW.
https://github.com/clehner/browsy
I haven't worked on this in a while but I wanted to put it out here in case it may inspire others.
For the actual HTML/CSS parsing and rendering, layout and painting, I would consider using netsurf or some of its dependencies, or Matt Brubeck's "Let's build a browser engine!" guide. The network and painting code would be specific to the Macintosh Toolkit and MacTCP, but parsing and layout could probably be taken from netsurf and its subprojects, or other existing projects.
It is written in C and builds in Apple's MPW.
https://github.com/clehner/browsy
I haven't worked on this in a while but I wanted to put it out here in case it may inspire others.
For the actual HTML/CSS parsing and rendering, layout and painting, I would consider using netsurf or some of its dependencies, or Matt Brubeck's "Let's build a browser engine!" guide. The network and painting code would be specific to the Macintosh Toolkit and MacTCP, but parsing and layout could probably be taken from netsurf and its subprojects, or other existing projects.