Callback methods will get called from within Specter Desktop Core for various reasons. You can implement them in your service-class in order to react on those occasions.
cryptoadvance.specter.services.callbacks file for all the specific callbacks.
Some important one is the
after_serverpy_init_app which passes a
Scheduler class which can be used to setup regular tasks. A list of currently implemented callback-methods along with their descriptions are available in