~/.config/font-manager/local.conf

local.conf

<?xml version="1.0"?>
<!DOCTYPE fontconfig SYSTEM "fonts.dtd">
<fontconfig>
  <alias>
    <family>monospace</family>
    <prefer><family>PragmataPro Mono</family></prefer>
    <default><family>PragmataPro Mono</family></default>
  </alias>
  <alias>
    <family>serif</family>
    <prefer><family>Liberation Serif</family></prefer>
    <default><family>Liberation Serif</family></default>
  </alias>
  <alias>
    <family>sans-serif</family>
    <prefer><family>Roboto</family></prefer>
    <default><family>Roboto</family></default>
  </alias>
  <!-- PragmataPro Mono looks better than all other monospace fonts -->
  <match target="pattern">
    <test qual="any" name="family"><string>PragmataPro</string></test>
    <edit name="family" mode="assign" binding="same"><string>PragmataPro Mono</string></edit>
  </match>
  <match target="pattern">
    <test qual="any" name="family"><string>Droid Sans Mono</string></test>
    <edit name="family" mode="assign" binding="same"><string>PragmataPro Mono</string></edit>
  </match>
  <match target="pattern">
    <test qual="any" name="family"><string>Consolas</string></test>
    <edit name="family" mode="assign" binding="same"><string>PragmataPro Mono</string></edit>
  </match>
  <match target="pattern">
    <test qual="any" name="family"><string>Monaco</string></test>
    <edit name="family" mode="assign" binding="same"><string>PragmataPro Mono</string></edit>
  </match>
  <match target="pattern">
    <test qual="any" name="family"><string>Lucida Console</string></test>
    <edit name="family" mode="assign" binding="same"><string>PragmataPro Mono</string></edit>
  </match>
  <match target="pattern">
    <test qual="any" name="family"><string>Liberation Mono</string></test>
    <edit name="family" mode="assign" binding="same"><string>PragmataPro Mono</string></edit>
  </match>
  <match target="pattern">
    <test qual="any" name="family"><string>DejaVu Sans Mono</string></test>
    <edit name="family" mode="assign" binding="same"><string>PragmataPro Mono</string></edit>
  </match>
  <match target="pattern">
    <test qual="any" name="family"><string>Book</string></test>
    <edit name="family" mode="assign" binding="same"><string>PragmataPro Mono</string></edit>
  </match>
  <match target="pattern">
    <test qual="any" name="family"><string>Bitstream Vera Sans Mono</string></test>
    <edit name="family" mode="assign" binding="same"><string>PragmataPro Mono</string></edit>
  </match>
  <match target="pattern">
    <test qual="any" name="family"><string>Courier New</string></test>
    <edit name="family" mode="assign" binding="same"><string>PragmataPro Mono</string></edit>
  </match>
  <match target="pattern">
    <test qual="any" name="family"><string>Courier</string></test>
    <edit name="family" mode="assign" binding="same"><string>PragmataPro Mono</string></edit>
  </match>
  <match target="pattern">
    <test qual="any" name="family"><string>Source Code Pro</string></test>
    <edit name="family" mode="assign" binding="same"><string>PragmataPro Mono</string></edit>
  </match>
  <match target="pattern">
    <test qual="any" name="family"><string>monospace</string></test>
    <edit name="family" mode="assign" binding="same"><string>PragmataPro Mono</string></edit>
  </match>

  <!-- Roboto looks better than Arial at lowdpi -->
  <match target="pattern">
    <test qual="any" name="family"><string>Arial</string></test>
    <edit name="family" mode="assign" binding="same"><string>Roboto</string></edit>
  </match>
  <match target="pattern">
    <test qual="any" name="family"><string>Helvetica</string></test>
    <edit name="family" mode="assign" binding="same"><string>Roboto</string></edit>
  </match>
  <!-- Roboto is slightly more readable than Liberation Sans -->
  <match target="pattern">
    <test qual="any" name="family"><string>Liberation Sans</string></test>
    <edit name="family" mode="assign" binding="same"><string>Roboto</string></edit>
  </match>
  <match target="pattern">
    <test qual="any" name="family"><string>Open Sans</string></test>
    <edit name="family" mode="assign" binding="same"><string>Roboto</string></edit>
  </match>
  <!-- Georgia is too wide, impeding speed reading -->
  <match target="pattern">
    <test qual="any" name="family"><string>Georgia</string></test>
    <edit name="family" mode="assign" binding="same"><string>Liberation Serif</string></edit>
  </match>
  <!-- Times New Roman does not look quite as good as Liberation Serif -->
  <match target="pattern">
    <test qual="any" name="family"><string>Times New Roman</string></test>
    <edit name="family" mode="assign" binding="same"><string>Liberation Serif</string></edit>
  </match>

</fontconfig>