This is a collection of minimal web browser implementations. Each of them will go to an URL if supplied as a first argument, or to a default URL (google, gnome, Chroma Check respectively) if run without arguments.
Point one of these script to Chroma Check to see what color fonts which implementation supports. Visit Color Font Demo for the same purpose.
The oldest (GtkSharp WebKit) is about a decade old, as part of the Font Validator work. The python WebKitGTK example was written in mid-2023 to replace that; the python QT examples were written to look at OT-SVG support in Chromium and QT WebEngine.