The recipe seem to be from Martin Picard / Pied de cochon.
I was not able to find table of content online but if you can find his first book (sugar shack was second I think) at the local library maybe it would be worth checking if there is something on his canned recipe or terrine.
https://www.amazon.com/Au-Pied-Cochon-Martin-Picard/dp/1553653912
Otherwise I would probably start with a classic terrine like this https://www.youtube.com/watch?v=syUxiAphhzc and try to figure out what ingredients / layerw would be able to survive canning heating step.
See also this recipe : https://bobarno.com/thiefhunters/duck-in-a-can/, duck in a can was actually one of he recipe served at Pied de cochon (see here https://www.youtube.com/watch?v=pmBFsm9iEZQ).
While looking for a video of that I have found that recipe : https://cuisinez.telequebec.tv/recettes/2956/canard-en-conserve
The serving from the can is fun / rustic but they probably used canning to help production / preservation. I listened to his amazing sugar shack tv show for a time (https://unchefalacabane.telequebec.tv/) and you can see his tought / working process. Sadly, no search engine so I cannot check if there was any "canned" recipe that could give some hints...