The phone asked: Which app is trying to install the file?

Zara groaned. “Unknown sources? I’m the source! It’s my own game!”

This time, instead of a scary warning, she saw an button. She pressed it.

Installing… Done.

She tapped Privacy . Then, she scrolled to the very bottom. There was a door marked Special permissions . She smiled. “This looks like the VIP section.”

She was a budding game developer. She had just created a beta version of her own game, "Space Pigeon," and her friend had sent her the installation file (the .apk ).

There was a single switch: Allow from this source . It was grayed out.