Relevant parts:
Partner represents and warrants that it shall not introduce into WhatsApp’s Systems or Infrastructure, the Sublicensed Encryption Software, or otherwise make accessible to WhatsApp any viruses or any software licensed under the General Public Licence or any similar licence (e.g. GNU Affero General Public License (AGPL), GNU General Public License (GPL), GNU Lesser General Public License (LGPL)) containing a “copyleft” requirement during performance of the Services.
Partner shall not: (i) combine Sublicensed Encryption Software with any software licensed under any version of or derivative of the GNU General Public License (e.g.; GNU Affero General Public License (AGPL), GNU General Public License (GPL), GNU Lesser General Public License (LGPL) in any manner that could cause, or could be interpreted or asserted to cause, the Sublicensed Encryption Software or any modifications to the Sublicensed Encryption Software to become subject to the terms of any version of or derivative of the GNU General Public License or other copyleft open source software
i THINK they’re saying that they sublicense a library to do encryption in order to talk to WhatsApp and that it’s this software that they won’t be allowed to be included in GPL-licensed software because it may be that in the future that implies a release of source code?
this doesn’t seem unreasonable as long as you can create a facade or abstraction that’s NOT GPL-licensed to interact with WhatsApp that then interacts with your GPL code?
or i could be misreading entirely