I'm developing a web based video game to be used internally at my company. It's not going to be sold to anyone and will only be used internally. I want to make sure all the artwork I'm using isn't copyrighted. I use a lot of the sprites and assets that are found on the phaser examples website https://phaser.io/examples. Does anyone know if these are free to use or copyrighted?. My management is having me doublecheck this.