Apache 2 is a permissive (think "pushover") license that allows proprietary forks. If the original were GPL or another copyleft license, then this would indeed have been illegal.

Can you? The relevant bit from the license seems to be:

> You may add Your own copyright statement to Your modifications and may provide additional or different license terms and conditions for use, reproduction, or distribution of Your modifications, or for any such Derivative Works as a whole, provided Your use, reproduction, and distribution of the Work otherwise complies with the conditions stated in this License.

I'm not clear how to interpret that "as a whole" bit combined with "otherwise complies".

Essentially the most that is really required by permissive licenses (Apache, BSD, MIT and their ilk) is a preservation of the license text, if even that. Anything else beyond that is open to change. So anyone can take any project licensed as such, and relicense with something more or less business-friendly, regardless of whether all contributors agree or not. That's what it means to be permissive.

That's not my understanding at all. You can't just relicense BSD code. You can incorporate it and distribute it with your own code that's under another license, but you couldn't just clone the FreeBSD source tree, 'sed s/BSD/My Own License', and call it good.

As long as you keep the previous license text somewhere and note what it applies to then I don't see the problem? FUTO does both in the NOTICE file:

>The license below applies only to the original AOSP keyboard code, which is up to commit d847619a2b48945465f840b8d81644fa455cc115. > Copyright (c) 2008, The Android Open Source Project

> Licensed under the Apache License, Version 2.0 (the "License");

> you may not use this file except in compliance with the License.

> ...

Relicense as in add another license with whatever restrictions they desire, because literally anything aside from changing/removing the original license itself goes.