The Apache License states:
“You must give any other recipients of the Work or Derivative Works a copy of this License;”
So if you’ve copied a bunch of functions from some Apache-licensed code (so it’s not just linking, you’ve borrowed code) into a product that is not itself Apache-licensed, what’s a good way to indicate that the license you included only applies to some bits of code in your product, not to the product as a whole? (To avoid the suggestion that the product as a whole is freely copyable.)
Should a list of projects you’ve borrowed from and their various licenses be included in the “About” screen for the product, insisting that the licenses only apply to those bits? I’m asking because that seems to make sense, but I don’t recall seeing that anywhere.
From a coding perspective, try your best to segregate and encapsulate the Apache parts.
From a license perspective, I would just note in the About screen “Some aspects of the $myproduct codebase covered under the Apache license” or something like that. You don’t need to specify which pieces, unless there’s a specific, named algorithm that you’re borrowing,