How does clueful get a list of all installed iOS applications?

I just installed Clueful by BitDefender on iOS. This application scans all the installed applications on my iPhone.

Given that iOS sandboxes all app data and my app cannot access other installed apps, how does Clueful pull it off?

Solution

BitDefender only checks if a URL Scheme for the installed app exists.

you can check if an installed app supports a URL with:

if ([[UIApplication sharedApplication] canOpenURL:[url absoluteURL]]) {
    //Your code
}

here is a Wiki with many known URL Schemes