From first-hand authority, some encrypted/secure apps have client-side feature detection. Leaking features doesn’t count as violating a standard. May be running

From first-hand authority, some encrypted/secure apps have client-side feature detection. Leaking features doesn’t count as violating a standard. May be running something like a named entity recognizer or keyword/category recognizer that is “sufficiently” anonymized. This on photos too; of course this can be adjusted for device parameters, battery availability, and geolocation. I cannot speak to WhatsApp specifically, but note this directly from at least one other popular messaging app. I would absolutely assume no encryption exists. Rats in the opera house.