/usr/lib/ghc-doc/hoogle/libghc-stringbuilder-doc.txt is in libghc-stringbuilder-doc 0.5.0-6build1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/ghc-doc/hoogle/../../../share/doc/libghc-stringbuilder-doc/html/stringbuilder.txt