Any font-face that uses "src: url(" is marked as a remote resource in CSSParser::parseFontFaceSrc(), and all remote fonts get their content re-parsed in CachedSVGFont::ensureCustomFontData(). Note that this is not a regression - this never worked, even without the SVG -> OTF converter.
Created attachment 248199 [details] Reproduction
I am able to reproduce this bug in Safari 15.5 / Safari Technical Preview 149 on macOS 12.4 using attached "Reproduction" test case. It does not render any text while all other browsers (Chrome Canary 105 and Firefox Nightly 104) shows "A" as rendered on the test case. Thanks!
<rdar://problem/97201147>