/usr/share/man/man3/brlapi_readPacketHeader.3.gz is in libbrlapi-dev 5.2~20141018-5.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/man/man3/brlapi_protocol.3.gz
/usr/share/man/man3/brlapi_protocol.3.gz