Many countries have a "formula" (legal definition) for a "contract", which include fair exchange of something for something else, e.g. time and labor for money.

Many countries have a "formula" (legal definition) for a "contract", which include fair exchange of something for something else, e.g. time and labor for money. If Google forces their developers to work for free (labor for nothing), then it fails to meet legal definition of the contract. IMHO, such "forced labor for free" is a form of slavery. Slavery is forbidden by law. If a developer want to publish his project under Google brand, then exchange may be considered as fair (project code for Google branding).