I have an app that I've been using for over 10 years now.
When I searched for that app on the App Store, it didn't show up. (both in the US, Japan, and Korean stores)
There's a phenomenon where the app crashes and dies when performing a specific function.
So I'm trying to develop an app that's very similar to that app.
When I migrate or restore after changing or initializing my device, the previously installed app is installed on the home screen.
There are several apps that don't show up on the App Store and seem to have been removed by the developer.
Some apps have a blank icon image on the home screen, and when you click on them, a pop-up appears saying that they can't be installed and asks if you want to delete the icon.
Some apps are still installed. Some functions are broken because the developer stopped maintaining them for a long time. They can't be searched on the store either.
What are the differences and similarities between these two apps?