For some reason
fc-match does not like to match
$ fc-match monospace DejaVuSansMono.ttf: "DejaVu Sans Mono" "Book" $ fc-match monospace:bold DejaVuSansMono.ttf: "DejaVu Sans Mono" "Book" $ fc-match monospace:weight=200 DejaVuSansMono-Bold.ttf: "DejaVu Sans Mono" "Bold"
According to the documentation (https://www.freedesktop.org/software/fontconfig/fontconfig-user.html)
weight=200 should be the same, but apparently they are not.
Some applications (especially Java) are using
monospace:bold to find the bold monospace font, but they get the normal one which is then artificially emboldened, which looks very ugly.
Edit: This only happens with fontconfig 2.13.0, which is used by Ubuntu 18.10. Earlier and later version used by 18.04 and 19.04 are fine.