How does the WhatsApp web client still work with the latest iOS update (SDK version 13.0+)?

Question

Dark mode support was added to version 2.20.31 (released in March of 2020) of the WhatsApp client. This is an iOS 13-only feature, and from the look & feel it appears to

Answer 1

This is WhatsApp latest entitlements file:

    com.apple.developer.icloud-container-identifiers
    
        57T9237FN3.net.whatsapp.WhatsApp
    
    com.apple.developer.pushkit.unrestricted-voip
    
    com.apple.developer.ubiquity-container-identifiers
    
        57T9237FN3.net.whatsapp.WhatsApp
    
    application-identifier
    UKFA9XBX6K.net.whatsapp.WhatsApp
    com.apple.developer.carplay-messaging
    
    aps-environment
    production
    com.apple.developer.icloud-container-environment
    Production
    com.apple.developer.associated-domains
    
        applinks:api.whatsapp.com
        applinks:v.whatsapp.com
        applinks:chat.whatsapp.com
        applinks:wa.me
    
    com.apple.developer.siri
    
    com.apple.developer.team-identifier
    57T9237FN3
    com.apple.developer.icloud-services
    
        CloudDocuments
        CloudKit
    
    com.apple.security.application-groups
    
        group.net.whatsapp.WhatsApp.shared
        group.com.facebook.family
        group.net.whatsapp.WhatsApp.private
        group.net.whatsapp.WhatsAppSMB.shared
        group.net.whatsapp.family
    

This specific entitlement seems to be the reason that they are allowed to not report an incoming call:

com.apple.developer.pushkit.unrestricted-voip

I can't find any documentation regarding this entitlement, so I'm pretty sure they have been given a special permission by Apple.