LOCAL_APPDATA_FONTCONFIG_CACHE directories are popping up everywhere

[Jim Reisert AD1C]

Recently, I seem to have LOCAL_APPDATA_FONTCONFIG_CACHE directories
popping up everywhere:

./DX4WIN/awd/RDA/LOCAL_APPDATA_FONTCONFIG_CACHE
./DXspots/LOCAL_APPDATA_FONTCONFIG_CACHE
./QSL/address/LOCAL_APPDATA_FONTCONFIG_CACHE
./QSL/LOCAL_APPDATA_FONTCONFIG_CACHE
./unified/callsigns/LOCAL_APPDATA_FONTCONFIG_CACHE
./unified/dx4win9/LOCAL_APPDATA_FONTCONFIG_CACHE
./unified/LOCAL_APPDATA_FONTCONFIG_CACHE

Does anyone know what might cause this, and how to stop it?

I do not have fontconfig installed, I only have these "font" files in /usr/bin:

/usr/bin/cygfontconfig-1.dll
/usr/bin/cygfontenc-1.dll
/usr/bin/cygXfont2-2.dll
/usr/bin/pdffonts.exe

-- 
Jim Reisert AD1C, <jjreisert@alum.mit.edu>, https://ad1c.us