I noticed that some of the built-in playgrounds have a file called LearningTrail.xml, with contents that look like this: ?xml version="1.0" encoding="UTF-8"? trail version="1.1" name="0103"   steps     step type="context"       blocks         block type="title"           title id="MfZ-Gx-dNg"What’s An Action?/title         /block         block type="image" source="content-whats-an-action" height="0.75"           description id="AcK-pe-jkX"A snail with four circles above it, showing the snail can scale, move forward and back, rotate, and fade in and out./description         /block         block type="text"           text id="jYg-QZ-KMx"In addition to animations, you can also scale, move, rotate, and fade your models using actions./text         /block                  block type="buttons" alignment="trailing"           button href="@nextStep" symbol="arrow.right.circle.fill"             text id="BMD-jU-Xiz"Ready?/text           /button         /block       /blocks     /step ... lots more The result looks like this: image link - https://github.com/aheze/DeveloperAssets/blob/master/IMG_5DAB4F43BA78-1.jpeg I can't find any documentation on this... will this be considered a private API? Are we allowed to make our own LearningTrail for our Swift Student Challenge submission?