Many developers think that contracts are the concerns of only sales people and executives. But this is not the case.  Even a scrum team works under contracts. Contracts like DoR( Definition of Ready) and DoD (Definition of done) are the two contracts which every scrum team must have. DoR is an agreement between product owner and scrum team. DoD is a contract where the team must meet their requirements. It is also signed between PO and scrum team.  There can be many other contracts like Interteam contracts and organizational contracts. Read the complete article here: https://www.scrumalliance.org/community/articles/2016/may/contract-negotiations-in-a-scrum-team