In Horizon 2020 no specific requirements to identify background within the project proposals exist.
The Horizon 2020 Rules for Participation and the General model GA oblige the parties “to identify in any manner and agree in writing” upon the background for the project. Although not mandatory, it is advised to agree on background before the Grant Agreement is signed, to ensure that beneficiaries have access rights to what is needed to implement the action or exploit the project results.
According to the needs of the project participants, the agreement on background may be a separate agreement (e.g. if it concerns only certain beneficiaries) or may be part of the Consortium Agreement (e.g. attachment 1 of the DESCA 2020 model CA).