What’s fixed

• A browser that asks for AVIF no longer 500s on a transformed image. libvips can report a format among the ones it reads without carrying the plugin that writes it — Debian splits AV1 encoding into its own package, so a stock image had every reason to believe it could produce AVIF and none to actually try. The AV1 encoder is now installed, and a format is only offered to a browser once it has genuinely been encoded, not merely found in the list of things libvips claims to support — so the same class of gap degrades to the next format instead of failing the request, on any build where an encoder turns out to be missing.