/usr/lib/ghc-doc/hoogle/libghc-x509-validation-doc.txt is in libghc-x509-validation-doc 1.6.5-2.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/ghc-doc/hoogle/../../../share/doc/libghc-x509-validation-doc/html/x509-validation.txt