The license could include provisions forbidding the distribution of the source and object code, and provisions saying that the original owner maintains all righ

The license could include provisions forbidding the distribution of the source and object code, and provisions saying that the original owner maintains all rights to their code and your code, and the source code may be used for the sole purpose of contributing improvements back to the original owners. In practice, no one uses that type of license, hence the confusion between free and open source.