If you installed infinality-bundle or the patched freetype2-infinality you'll most likely recently have run into an error relating to the harfbuzz package (>= 1.4.1-1), specifically something like: /usr/lib/libharfbuzz.so.0: undefined symbol: FT_Get_Var_Blend_Coordinates.

This is because the packages provided by the Infinality repositories or even the freetype2-infinality on AUR are and have been outdated for quite some time, since infinality-bundle's creator, bohoomil, has been missing/unresponsive for the past few months. freetype2 since has gotten new features and a changed ABI, one of which is a symbol named FT_Get_Var_Blend_Coordinates which the updated libharfbuzz tries to reference.

What this means for you is: you'll need a freetype2 version >= 2.7.1 where this change was initially introduced. Since the future of the infinality-bundle is uncertain this is a good time as any to bite the bullet and remove it completely from your system until more is known. The font rendering won't be exactly the same, but with a few tweaks it will at least be similar.