AppDaemon apps are apps for AppDaemon
Since not all users are running AppDaemon, AppDaemon is not enabled by default in HACS.
AppDaemon Has to be installed before doing the configuration with HACS.
Enable AppDaemon apps in HACS
Add a checkmark to the left of AppDaemon apps in the UI configuration for HACS.
For more about configuring HACS with the UI have a look here
AppDaemon apps download location
Any AppDaemon app downloaded with HACS is stored in
appdaemon/apps/ in your Home Assistant configuration directory.