Please obtain, read, and make sure you understand the full text of the APSL. For a quick first glance, here is an excerpt (emphasis added):

2. (...) Apple hereby grants You, (...) a world-wide, royalty-free, non-exclusive license (...) to do the following: 2.1 Unmodified Code.  You may (...) Externally Deploy verbatim, unmodified copies of the Original Code, for commercial or non-commercial purposes, provided that in each instance: (a) You must retain (...) the copyright and other proprietary notices (...) (b) You must include a copy of this License (...) and You may not (...) alter or restrict this License (...) 2.2 Modified Code.  You may modify (...) and Externally Deploy Your Modifications and Covered Code, for commercial or non-commercial purposes, provided that (...): (a) You must satisfy all the conditions of Section 2.1 (...) (b) You must duplicate (...) the notice in Exhibit A in each file of the Source Code of all Your Modifications, and cause the modified files to carry prominent notices stating that You changed the files and the date of any change; and (c) If You Externally Deploy Your Modifications, You must make Source Code (...) available (...) under the terms set forth in this License, including the license grants set forth in Section 3 below (...). 2.3 Distribution of Executable Versions.  (...) must include a prominent notice, in the code itself as well as in related documentation, stating that Source Code of the Covered Code is available under the terms of this License with information on how and where to obtain (...) Source Code.

3. Your Grants. (...) You hereby grant (...) a non-exclusive, royalty-free, perpetual, irrevocable license, (...) of the same scope and extent as Apple's licenses under Sections 2.1 and 2.2 above.

4. Larger Works. You may create a Larger Work by combining Covered Code with other code not governed by the terms of this License and distribute the Larger Work as a single product. (...)