author: hsjoberg
SERVICE in the pay protocol MAY include a text/long-desc entry in the metadata payload, with the intended purpose being a longer description of the payment. It MAY contain newlines and SHOULD provide a more detailed description of the payment.
WALLET MUST upon recognizing the text/long-desc metadata use it as the payment description in the pay screen.
WALLET MAY display the text/long-desc text together with the text/plain text.
If text/long-desc is not included in the metadata payload,text/plain MUST instead be used on the pay screen.