/usr/lib/ghc-doc/hoogle/libtagc.txt is in libghc-libtagc-doc 0.12.0-5.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/ghc-doc/hoogle/../../../share/doc/libghc-libtagc-doc/html/libtagc.txt
/usr/lib/ghc-doc/hoogle/../../../share/doc/libghc-libtagc-doc/html/libtagc.txt