Description
Bug report
Bug summary
The svg backend currently exposes the svg.fonttype = svgfont option, which embeds fonts into the svg file using the "svg fonts" feature which appears to be essentially unsupported anywhere and removed from the svg standard (https://caniuse.com/#feat=svg-fonts https://developer.mozilla.org/en-US/docs/Web/SVG/Tutorial/SVG_fonts). The code path was also not working at all on Py3 (#10046).
I would thus suggest deprecating support for svg fonts.
A possibility to still allow embedding the font file into the svg file would be to use the apparently more popular WOFF(2) format, see https://developer.mozilla.org/en-US/docs/Web/Guide/WOFF https://developer.mozilla.org/en-US/docs/Web/CSS/@font-face for the format, http://www.sameratiani.com/2011/10/16/embed-inline-webfonts-in-css.html for embedding the font into the svg file itself, and https://caniuse.com/#search=woff for support. A quick test suggests that this is supported but chrome/firefox, but not by inkscape, but at least inkscape emits a warning and replaces the embedded font by another one, whereas it appears to freeze with the current implementation of svg fonts.