The Canvas below is painted by using Canvas quirks (differences in browser implementations, not whether a feature is implemented). Each quirk is combined with browser-specific content to be rendered (just text below). They are all drawn, but Canvas blend modes are used so that only the content for your specific browser is displayed.
No browser detection is done, and the Canvases we paint to are never read.
Your browser's Canvas quirks seem to match:
And here's some art using quirks, unique to Canvas implementations:
The following is a list of quirks that can be used for detection (currently we only check a subset) and whether they are present. They are cropped versions of a single draw call (stroke or fill) for a path. For details, please see a list of all quirks with code.
This works for all tested current browsers as of July 21st, 2014. When I have time available, I'll be submitting bug reports for these (hopefully they will be all fixed one day!)
All of the logic for handling quirks and conditional painting is contained in paint-tests.js.