/usr/lib/ghc-doc/hoogle/libghc-monadprompt-doc.txt is in libghc-monadprompt-doc 1.0.0.5-4.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/ghc-doc/hoogle/../../../share/doc/libghc-monadprompt-doc/html/MonadPrompt.txt