Timestamps are relative comparisons between effects and when they began applying to the game.
§ 480.1.b Core Rules PDF (officieel)
§ 480 If more than one effect applies in the same layer but no dependency is established, then Timestamp order is applied to the effects within that layer and sublayer
§ 480.1 When an effect begins applying, it establishes a time for which it is compared against other Game Effects for purposes of resolving Layered effects as its Timestamp.
