CommunityToolkit.Mvvm Messenger Pub/sub messaging for ViewModels (or any objects) without forcing a shared reference graph. Part of 8.x. TL;DR. Default to . Register handlers with the lambda and the modifier so you never capture . Inherit from and toggle at activation/deactivation to get automatic register/unregister. --- When to use this skill - Two or more ViewModels need to react to an event (login, theme change, save, navigation) without holding references to each other - A ViewModel needs to ask another VM for a value (request/reply) - You're scoping events to a sub-system or window with…