core/otf-source-han-sans/44-source-han-sans.conf

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE fontconfig SYSTEM "../fonts.dtd">
<fontconfig>

    <match target="scan">
        <test name="fullname" compare="eq">
            <string>Source Han Sans Medium</string>
        </test>
        <edit name="weight" mode="assign">
            <const>demibold</const>
        </edit>
    </match>
    
    <match>
        <test name="lang" compare="contains">
            <string>jp</string>
        </test>
        <test name="family">
            <string>sans-serif</string>
        </test>
        <edit name="family" mode="prepend">
            <string>Source Han Sans</string>
        </edit>
    </match>
</fontconfig>