I'd actually be very surprised if Firefox uses librsvg, considering that librsvg doesn't support much of the interactivity and animations that Firefox supports

I'd actually be very surprised if Firefox uses librsvg, considering that librsvg doesn't support much of the interactivity and animations that Firefox supports in SVGs. Looking roughly at the source code [0], it seems it has its own SVG engine. [0] https://github.com/mozilla/gecko-dev/tree/master/layout/svg https://github.com/mozilla/gecko-dev/tree/master/layout/svg https://github.com/mozilla/gecko-dev/tree/master/dom/svg https://github.com/mozilla/gecko-dev/tree/master/dom/svg