>>joseph+(OP)
This headline really is misleading. The source will still be released, it just means that the work leading up to a release will be in private. IMO, there's nothing wrong with that, since it's likely that a lot of the intermediate com mediates are likely just noise.
>>ycombi+011
The source for AOSP. Individual Android devices have never been open source (minus some very few exceptions), and they have no obligation to do so as AOSP is Apache/permissively licensed.
Note that the demand for secrecy is primarily driven by device manufacturers, not Google. Manufacturers want to keep their "secret sauce" from their competitors.