There is no explicit license info in the local directory.
I used "fontforge" to open the fontdata file (.pcf.gz file) in the
xorg-minimal-fonts/misc/ and found fontforge's menu
"Element->Other Info->BDF info" says the "COPYRIGHT" is
"Public domain font. Share and enjoy. Actually
"cat *.pcf.gz | gunzip | strings | grep 'Public domain'" also shows
the same string.
So I think the license of xorg-minimal-fonts should be Public Domain.