Optimization Pack Content:

• 30 000 Credits you can use to unlock bot skin parts (equivalent of 60 colors / 20 color patterns / 30 textures)
  
• 3D printing models of the different bots
  
• 10+ exclusive wallpapers (in 4K resolution)
  
• 1 exclusive player icon

You will find the DLC files in the game installation folder.
For most people it should be C:\Program Files (x86)\Steam\steamapps\common\Gladiabots.