Hey Axel. If there is any validity there, it is lost on me for sure. The Author was pretty specific and said: "After doing an iCloud restore the CarPlay app is missing from the device. How can I download the app? This has happened twice. Is it possible my backup is corrupted?"
I don't see how one can not see that they think the CarPlay app is gone from their device. Had they said, it was gone from their car that would be different. But saying it's gone from their device means they think they lost the CarPlay app. Which we know they couldn't lose an app which has never existed. CarPlay is a setting in Settings. Not an App. So, suggesting maybe Apple removed the App from the App Store, simply makes no sense at all. TL even suggested they look at their purchase history. WHY? There would be NO record of having downloaded an app which has never been in the App Store to begin with. The only thing I can surmise is TL simply didn't understand the question.
I guess I approach things differently. If I come along and another member posted a response, I'd want to make certain their answer was correct, before I'd add a solution which doesn't address the question. If I don't understand a question, I'll go try to answer something I do understand. Clearly, I'm just wired differently in this regard.
Anyway, good to see you!