It’s runs on a JVM, right? Presumably it could be decompiled and cleaned up (might be a massive task - but possible), and the reconstructed source would fall under the Apache license.
I thought the reason was the explicit patent language and lack of license virality.
The Apache license 2 is pretty clear that binary only distribution is allowed, but I think it’s also clear that the assumption is that source is available in some form. Otherwise, why would you care about derivative works?
As is, it would be possible to decompile the JVM code into something resembling source code and then distribute that with or without modification. Which just seems odd to me.
This is actually an interesting question. But I can’t see how a binary only distribution would be in the spirit of the Apache license.