Q1: What card must be trashed for this card's Start of Your Main Phase effect?
The cards are either "cards with the text 'DRACOMON'" or "cards with the text 'EXAMON'".
Q2: What do you mean by "cards with text?"
It refers to cards with the specified word or icon included in "name, trait, effect, inherited effect, <Overflow X>, jogress, digivolution requirements, burst digivolution". For example, a card with the text "Knightmon" refers to a card whose name is "Dark Knightmon" or whose effect says "Knightmon".
Lv.3 Dracomon BT20-007 R Rookie | Data | Dragon [Digivolve] [Bebydomon]: Cost 0 [Start of Your Main Phase] By trashing 1 card with [Dracomon] or [Examon] in its text in your hand, <Draw 1> and gain 1 memory. --- Inherited: [Your Turn] This Digimon gets +2000 DP.
Lv.3 Dracomon BT20-007 R Rookie | Data | Dragon [Digivolve] [Bebydomon]: Cost 0 [Start of Your Main Phase] By trashing 1 card with [Dracomon] or [Examon] in its text in your hand, <Draw 1> and gain 1 memory. --- Inherited: [Your Turn] This Digimon gets +2000 DP.
Lv.3 ドラコモン BT20-007 R 成長期 | データ種 | 竜型 「ベビドモン」:コスト0 【自分のメインフェイズ開始時】自分の手札から、「ドラコモン」/「エグザモン」の記述があるカード1枚を破棄することで、≪1ドロー≫し、メモリー+1。 --- Inherited: 【自分のターン】このデジモンをDP+2000。