I'm trying to bulk import cards to UrzaGatherer using the "merge" option. The .ugs files are all based on the "ID" field, but I can't find where these ID values are coming from. How can I find the ID values for a card, given the multiverse ID? For example, this is what the .ugs file looks like for a collection with a single card:
If I have a cards multiverse ID, or TCG ID, how can I generate the "ID" which appears to be specific to UrzaGatherer?