Deb 8.4 OpenSSL headers

[Nicholas Geovanis]

I can't tell which debian 8.4 package provides the C headers for OpenSSL,
the "Usual suspects" such as openssl-devel and the like do not exist,
dpkg-query doesn't seem to find anything likely. Would some kind person
give me a clue where to find the OpenSSL C header files in the Debian
packaging universe?
Many thanks....Nick G