Due to the grind to prestige your Character being made much easier in Patch 1.3.0, the Developers decided to reward Players who had put the time into prestiging their Character before the Patch. With every Level of Prestige obtained, the Player was granted one Legacy Prestige Clothing Item. These are the Entity Touched apparel, similar to the blood-soaked clothes you receive for obtaining a regular Level of Prestige.
This was a limited time event and only having reached Prestige prior to Patch 1.3.0, could you obtain these Clothing Items. The deadline was 24 November 2016. They are no longer available to earn in-game and will never be re-issued. There is no Legacy Prestige for any Character released after the event and licensed Characters released during it (namely Laurie Strode and The Shape).