There are many bugs on Android and iOS that can cause the system to crash. One of the things I like to see is a bug where typing certain symbols or alphabets causes the device to crash. It's been a long time since a bug like this appeared until a security research firm discovered a new bug in iOS.
Typing “”:: on any search bar in iOS regardless of the home screen, app drawer or settings – the system will temporarily hang and the open app will close and bring the user back to the home screen. According to reports, the disrupted system is caused by Springboard, which is an iOS system application that is like a launcher. However, this bug is not a security risk that will affect personal data or privacy. It's just a small bug that might annoy some users. After all who wants to type “”:: for no reason?