I started working on #LibreOffice again, two new developments:
It now instances variable fonts when embedding in PDF instead of drawing the outlines as PDF vectors (using PDF Type 3 fonts), which is more efficient and allows the text to be rendered as fonts not graphics.
This uses #HarfBuzz subsetter under the hood, so while at it, I replaced most of LibreOffice’s ancient (CVE-happy) low-level font subsetting code, with HarfBuzz subsetter.
CFF2 fonts are still drawn as graphics, but next of version of HarfBuzz will support downgrading CFF2 to CFF after instancing, and I plan to use that when it is available.