/usr/share/mysql/charsets/ is in percona-xtradb-cluster-server-5.6 5.6.21-25.8-0ubuntu3.
This file is owned by root:root, with mode 0o755.
..
/usr/share/mysql/charsets/Index.xml
/usr/share/mysql/charsets/README
/usr/share/mysql/charsets/armscii8.xml
/usr/share/mysql/charsets/ascii.xml
/usr/share/mysql/charsets/cp1250.xml
/usr/share/mysql/charsets/cp1251.xml
/usr/share/mysql/charsets/cp1256.xml
/usr/share/mysql/charsets/cp1257.xml
/usr/share/mysql/charsets/cp850.xml
/usr/share/mysql/charsets/cp852.xml
/usr/share/mysql/charsets/cp866.xml
/usr/share/mysql/charsets/dec8.xml
/usr/share/mysql/charsets/geostd8.xml
/usr/share/mysql/charsets/greek.xml
/usr/share/mysql/charsets/hebrew.xml
/usr/share/mysql/charsets/hp8.xml
/usr/share/mysql/charsets/keybcs2.xml
/usr/share/mysql/charsets/koi8r.xml
/usr/share/mysql/charsets/koi8u.xml
/usr/share/mysql/charsets/latin1.xml
/usr/share/mysql/charsets/latin2.xml
/usr/share/mysql/charsets/latin5.xml
/usr/share/mysql/charsets/latin7.xml
/usr/share/mysql/charsets/macce.xml
/usr/share/mysql/charsets/macroman.xml
/usr/share/mysql/charsets/swe7.xml