/usr/lib/ghc-doc/hoogle/authenticate-oauth.txt is in libghc-authenticate-oauth-doc 1.4.0.6-1build8.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/ghc-doc/hoogle/../../../share/doc/libghc-authenticate-oauth-doc/html/authenticate-oauth.txt