... meanwhile Github doesn't support viewing rendered SVG files when you click on a .svg file, yet they have viewers for 3D objects and maps that render in SVG.
It's frustrating how difficult it is to get anybody at Github do work on small things since there's "no manager" and everybody wants to focus on grandiose projects.
Browsers are really not good at rendering SVG. Both WebKit and Gecko are riddled with bugs once you start using the non-trivial features of SVG. Worse still, browsers don't even support the latest version of SVG, which suffered a fate similar to ECMAScript 4. However, vector illustrating programs will happily generate files which use the browser-incompatible newer versions.
So while it may be possible to target SVG as a backend for rendering basic drawings, displaying arbitrary SVG files is, in practice, a lost cause.
They don't have to send the straight svg for preview. They could either modify it for compatibility or at least render it server-side to raster and send it over. It's not impossible, at any rate.
It's frustrating how difficult it is to get anybody at Github do work on small things since there's "no manager" and everybody wants to focus on grandiose projects.