Artificial intelligence initiates a second set of queues – so-called proactive ones – by scanning unencrypted data that WhatsApp collects about its users and comparing it against suspicious account information and messaging patterns [...] as well as terms and images that have previously been deemed abusive. The unencrypted data available for scrutiny is extensive. It includes the names and profile images of a user’s WhatsApp groups as well as their phone number, profile photo, status message, phone battery level, language and time zone, unique mobile phone ID and IP address, wireless signal strength and phone operating system, as a list of their electronic devices, any related Facebook and Instagram accounts, the last time they used the app and any previous history of violations.

E: Upon looking into this further, the source from ProPublica makes it clear that the proactive queue cannot decrypt your messages. This was unclear in the linked article and only clarified separately in the ProPublica one. Despite that, I think the point still stands: WhatsApp gathers a ton of your personal data, and can reveal that to authorities on request.