/usr/lib/ghc-doc/hoogle/idna.txt is in libghc-idna-doc 0.2-2build2.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/ghc-doc/hoogle/../../../share/doc/libghc-idna-doc/html/idna.txt
/usr/lib/ghc-doc/hoogle/../../../share/doc/libghc-idna-doc/html/idna.txt