The following is an extract from 'Rules for the ESC 2017'. I haven't been to locate a more recent version. This section covers the jury procedure, and twice refers to the mysterious 'Green Document'.
1.3.3) NATIONAL JURIES’ VOTING PROCEDURE
Each National Jury shall meet in its own country on the day of the second Dress Rehearsal of the Semi-Final in which it is responsible for voting and on the day of second Dress Rehearsal of the Final. The National Juries shall watch the live transmission of the second Dress Rehearsals and proceed to vote in accordance with the EBU’s instructions included in the so-called "Green Document”.
All members of the National Juries shall receive their own voting sheet (to be distributed by the pan-European televoting partner) and shall be required to send a form, duly completed, in which they confirm that they will comply with the voting instructions, as well as a signed declaration in which they undertake to vote independently.
After the presentation of all the songs in a given Show, each jury member shall rank all the songs which have been performed in the Show in question and the points shall be allocated in accordance with the system described under Section 1.1.3.
Each National Jury’s deliberations shall be monitored by a notary, whose tasks shall be to:
ensure compliance with the voting rules;
to avoid any calculation error, collect, check and certify, before the ranks are allocated and entered into a computer by the chairperson:
the calculation of the results and the completed voting papers established by the chairperson;
send by fax all the certified voting papers to the pan- European televoting partner.
Respect for this provision shall be the responsibility of the Participating Broadcasters.
The Chairperson and the Notary shall remain available and must be attainable at any time until the beginning of the retransmissions of the second Dress Rehearsals of the Shows and during the Shows themselves.
If it appears that votes are casted only in the intent to abuse the voting system or to false the final results or have not been undertaken in accordance with the Green Document, the EBU Permanent Services, in consultation with the Pan-European televoting partner, the independent auditor of the voting process and the chairman of the Reference Group reserve the right to remove such votes for allocating the ranks.
Each Participating Broadcaster shall ensure that its National Jury is fully independent and votes in total impartiality. It shall cooperate with the EBU and the independent auditor in connection with all matters regarding National Jury voting.