You can treat a learn card as a card that has some minor value effect like draw a card or create a token that can tutor for a lesson card from your sideboard
There are a couple of rules you should always be aware of
Apart from this article, I dont know anything about playtesting in Pokmon, especially not during the WotC era
While a handful of cards that are particularly funny, reference iconic old cards, or are somehow useful in real life (like Ashnod's Coupon or Richard Garfield, Ph.D.) might have a little value, you'll be cracking packs of Unstable for the jokes and novelty, rather than in the hopes of opening a valuable rare
Community estimates place them at roughly 12 per case (12 Japanese boxes)
Enchantment Rotting Rats When this creature enters, each player discards a card