Q1: What does a card with "X in its text" refer to?
It refers to a card that contains the specified text or icon in its name, traits, effects, inherited effects, (Rule), digivolution requirements, DNA digivolution, DigiXros requirements, burst digivolve, App Fusion, Link, or Assembly requirements. For example, a card with Knightmon in its text would include cards with the name DarkKnightmon and cards with the text Knightmon in their effects.
Lv.3 DemiDevimon P-239 P rookie | Virus | Evil <Blocker> [On Deletion] By placing this Digimon card as the bottom digivolution card of 1 of your Digimon with [Myotismon] in its text, that Digimon may digivolve into a Digimon card with [Myotismon] in its name in your hand without paying the cost. --- [On Deletion] By trashing 1 card in your hand, delete 1 of your opponent's level 4 or lower Digimon.