/usr/share/man/man3/curl_msnprintf.3.gz is in libcurl4-doc 7.47.0-1ubuntu2.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/man/man3/curl_mprintf.3.gz
/usr/share/man/man3/curl_mprintf.3.gz