/usr/lib/ghc-doc/hoogle/libghc-hashmap-doc.txt is in libghc-hashmap-doc 1.3.0.1-7build1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/ghc-doc/hoogle/../../../share/doc/libghc-hashmap-doc/html/hashmap.txt