Graven Lore

• WOTC Official Reminder Textofficial rules
  Scry — Look at the top N cards of your library, then put any number of them on the bottom of your library and the rest on top in any order.

• WWizards of the Coast2021-02-05
  Official Ruling
  Snow isn’t a type of mana. If an effect says you may spend mana as though it were any type, you can’t pay for using mana that wasn’t produced by a snow source.
• WWizards of the Coast2021-02-05
  Official Ruling
  Some cards have additional effects for each spent to cast them. You can cast these spells even if you don’t spend any snow mana to cast them; their additional effects simply won’t do anything.
• WWizards of the Coast2021-02-05
  Official Ruling
  The Kaldheim set doesn’t have any cards with mana costs that include , but some previous sets do. If an effect says such a spell costs less to cast, that reduction doesn’t apply to any costs. This is also true for activated abilities that include in their activation costs and effects that reduce those costs.
• WWizards of the Coast2021-02-05
  Official Ruling
  If you cast Graven Lore without spending snow mana, you’ll just draw three cards.
• WWizards of the Coast2021-02-05
  Official Ruling
  If Graven Lore is copied, no mana was spent to cast the copy, so you’ll just draw three cards.
• WWizards of the Coast2021-02-05
  Official Ruling
  Snow is a supertype, not a card type. It has no rules meaning or function by itself, but spells and abilities may refer to it.
• WWizards of the Coast2021-02-05
  Official Ruling
  The symbol is a generic mana symbol. It represents a cost that can be paid by one mana that was produced by a snow source. That mana can be any color or colorless.

Rulings via Scryfall