/usr/lib/x86_64-linux-gnu/libldap.a is in libldap2-dev 2.4.31-1+nmu2ubuntu8.4.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/x86_64-linux-gnu/libldap_r.a
/usr/lib/x86_64-linux-gnu/libldap_r.a