/usr/lib/ghc-doc/hoogle/base-unicode-symbols.txt is in libghc-base-unicode-symbols-doc 0.2.2.4-3.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/ghc-doc/hoogle/../../../share/doc/libghc-base-unicode-symbols-doc/html/base-unicode-symbols.txt