CarPlay: Can third-party audio apps add a Search/Siri button next to the Now Playing button like Apple Music?

Hi,

In Apple Music on CarPlay, there is a Search button shown next to the Now Playing (NPS) button in the top navigation bar. Tapping this Search button activates Siri voice search.

I want to understand:

• Does CarPlay allow third-party audio apps to add a similar Search button in the top bar (next to the Now Playing button)? Which can be used to trigger Siri from the screen UI (not steering-wheel button or “Hey Siri”)?

• Is there any supported approach for screen-based Siri activation other than the guidance here: https://developer.apple.com/documentation/carplay/cplisttemplate#Integrating-Siri-Into-Your-Template-App

Basically, is the Apple Music search/Siri button a publicly available CarPlay capability, or is it system-reserved?