/usr/share/man/man3/ is in libdlm-dev 4.0.1-0ubuntu1.
This file is owned by root:root, with mode 0o755.
..
/usr/share/man/man3/libdlm.3.gz
/usr/share/man/man3/dlm_create_lockspace.3.gz
/usr/share/man/man3/dlm_unlock.3.gz
/usr/share/man/man3/dlm_lock.3.gz
/usr/share/man/man3/dlm_lock_wait.3.gz
/usr/share/man/man3/dlm_ls_lock_wait.3.gz
/usr/share/man/man3/dlm_cleanup.3.gz
/usr/share/man/man3/dlm_ls_lock.3.gz
/usr/share/man/man3/dlm_close_lockspace.3.gz
/usr/share/man/man3/dlm_ls_lockx.3.gz
/usr/share/man/man3/dlm_ls_unlock.3.gz
/usr/share/man/man3/dlm_ls_pthread_init.3.gz
/usr/share/man/man3/dlm_open_lockspace.3.gz
/usr/share/man/man3/dlm_unlock_wait.3.gz
/usr/share/man/man3/dlm_ls_unlock_wait.3.gz
/usr/share/man/man3/dlm_new_lockspace.3.gz
/usr/share/man/man3/dlm_dispatch.3.gz
/usr/share/man/man3/dlm_release_lockspace.3.gz
/usr/share/man/man3/dlm_get_fd.3.gz
/usr/share/man/man3/dlm_pthread_init.3.gz