A missing family the suite's font store has (Google Fonts, Noto) gets a
Download button. The first one asks the user to allow downloading fonts,
then craft-libs' craft-font-store installs pinned, checksum-verified files
into the Craft apps' shared font folder on a thread of its own. The font
scan reads that folder; once installed the text fits the real font.
font.download / font.downloads drive the store as its agent: refused while
downloading is off, never able to turn it on. Desktop only.