The player extracting a praetor token from an elite guard
In DOOM, Praetor Tokens are small chips collected from the armor suits of dead Elite Guards scattered around each map. Finding one grants the player a point with which to spend on suit upgrades, such as powerup effectiveness and effectiveness of the player's map. According to the codex entries on Elite Guards, these tokens are "kill chips" implanted into the Guards' uniforms to control them in the event of an uprising or mutiny, and the chips respond to a Lazarus Wave signature that can only be broadcast by Samuel Hayden or Olivia Pierce - a Lazarus Wave event occurred prior to the game's events, thus explaining the presence of numerous dead Elite Guard soldiers throughout the game.
Praetor Tokens, now called Praetor Suit Upgrade Points, re-appear in Doom Eternal as a collectible allowing the Doom Slayer to improve his Praetor Suit's equipment and other attributes. However, rather than being held by deceased elite UAC guards, the Slayer receives Praetor upgrade points from the spirits of fallen Night Sentinels strewn about the environments he visits and behind locked areas of the Fortress of Doom.