/usr/share/xindy/lang/slovak/ is in xindy-rules 2.4-1.1.
This file is owned by root:root, with mode 0o755.
..
/usr/share/xindy/lang/slovak/large-cp1250-lang.xdy
/usr/share/xindy/lang/slovak/large-cp1250-test.xdy
/usr/share/xindy/lang/slovak/large-cp1250.xdy
/usr/share/xindy/lang/slovak/large-latin2-lang.xdy
/usr/share/xindy/lang/slovak/large-latin2-test.xdy
/usr/share/xindy/lang/slovak/large-latin2.xdy
/usr/share/xindy/lang/slovak/large-utf8-lang.xdy
/usr/share/xindy/lang/slovak/large-utf8-test.xdy
/usr/share/xindy/lang/slovak/large-utf8.xdy
/usr/share/xindy/lang/slovak/small-cp1250-lang.xdy
/usr/share/xindy/lang/slovak/small-cp1250-test.xdy
/usr/share/xindy/lang/slovak/small-cp1250.xdy
/usr/share/xindy/lang/slovak/small-latin2-lang.xdy
/usr/share/xindy/lang/slovak/small-latin2-test.xdy
/usr/share/xindy/lang/slovak/small-latin2.xdy
/usr/share/xindy/lang/slovak/small-utf8-lang.xdy
/usr/share/xindy/lang/slovak/small-utf8-test.xdy
/usr/share/xindy/lang/slovak/small-utf8.xdy