It is identified in an instruction that a player “must” complete. e.g., “You must recycle one of your runes” doesn’t target anything. You choose from among your runes as the spell or ability resolves. e.g., “Recycle a rune you control” targets a rune. You choose a rune you control as you put the spell or ability on the chain.
§ 355.10.f Core Rules PDF (officieel)
§ 355 2. Make relevant choices.
§ 355.10 A game object, player, or zone mentioned in the text of a spell, activated ability, or triggered ability is a target UNLESS any of the following are true:
