> In fact, what I'm trying to understand exactly is if I assume that you are correct that there is no difference, then why would Google require the contribution in the first place?
The difference isn't relevant 99% of the time, but it comes up if the maintainership of a work tries to re-license the work. Works without assigned ownership cannot practically be re-licensed, as you'd have to get individual consent from all owning parties.
This came up a lot when GPLv3 was introduced — many projects wanted to migrate from GPLv2 to GPLv3, but couldn't, because they never acquired legal ownership of contributed code, and so didn't have the right to re-license the contributors' code.
The difference isn't relevant 99% of the time, but it comes up if the maintainership of a work tries to re-license the work. Works without assigned ownership cannot practically be re-licensed, as you'd have to get individual consent from all owning parties.
This came up a lot when GPLv3 was introduced — many projects wanted to migrate from GPLv2 to GPLv3, but couldn't, because they never acquired legal ownership of contributed code, and so didn't have the right to re-license the contributors' code.