No Color Emoji in Flatpak
Currently, the Flatpak version of the app does not render color emoji. Instead, it usually shows them using their monochrome representation.
It seems, this can easily be fixed by putting a fontconfig config file into the apps's config/fontconfig/conf.d/99-noto-color-emoji.conf
with the following content:
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE fontconfig SYSTEM "fonts.dtd">
<fontconfig>
<alias>
<family>serif</family>
<prefer>
<family>Noto Color Emoji</family>
</prefer>
</alias>
<alias>
<family>sans-serif</family>
<prefer>
<family>Noto Color Emoji</family>
</prefer>
</alias>
<alias>
<family>monospace</family>
<prefer>
<family>Noto Color Emoji</family>
</prefer>
</alias>
</fontconfig>
Note: The configuration is taken from here.
Chances are that we might have to also ship a copy of the Color Emoji font (in this case: the Noto one).
Note 2: Unfortunately, putting such a config file either in the system wide fontconfig configuration directory nor in the user one seems to have an effect.