/usr/share/myspell/dicts/cs_CZ.dic is in myspell-cs 20040229-5.1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/myspell/dicts/../../hunspell/cs_CZ.dic
/usr/share/myspell/dicts/../../hunspell/cs_CZ.dic