In Kingdom Hearts II, Sora receives the Photon Debugger once he defeats the Hostile Program.
The Photon Debugger looks similar to the inhabitants of Space Paranoids, appearing to be constructed of computer circuitry. The Keychain's token is Tron's Identity Disk, just having less neon rings.
Its name comes from two words; debugging is a way to eliminate a computer virus or bugs, similar to how the Keyblade eradicates Heartless. Photons are the fundamental quantum particles that compose light, and Sora is the wielder of the Keyblade of Light.