The game Garry's Mod originally took assets and codes from the popular Half Life 2 mod JBmod.

The answer is true because Garry's Mod was indeed created by Garry Newman as a modification of Half-Life 2 and it heavily borrowed assets and codes from the popular Half-Life 2 mod called JBMod. Garry's Mod started off as a sandbox physics game mode within JBMod, allowing players to manipulate and interact with various objects and characters within the Half-Life 2 engine. However, Garry Newman eventually developed Garry's Mod as a standalone game, expanding upon the original mod and making it accessible to a wider audience.