Geary displays messages in serif font on Ubuntu 19.04
I'm running Geary (from master) on Ubuntu. I just upgraded from Ubuntu 18.10 to the current release 19.04, and now Geary is diplaying all messages in a serif font. Previously (on 18.10) they were displayed in sans serif.
I'm not sure whether Geary explicitly asks for sans serif, or just lets WebKit choose a default font to use. But in any case I think a sans serif font would be easier on the eyes for casual reading in an email program.