/usr/lib/ghc-doc/hoogle/libghc-haskell-lexer-doc.txt is in libghc-haskell-lexer-doc 1.0.1-3.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/ghc-doc/hoogle/../../../share/doc/libghc-haskell-lexer-doc/html/haskell-lexer.txt