Hello there! We are conducting a survey to better understand the user experience in making a first edit. If you have ever made an edit on Gamepedia, please fill out the survey. Thank you!
A source code is the term for the coding and programming behind a program/video game. Programs usually keep their source code a secret, so that people cannot easily hack or alter it. When a game releases it's source code to the public, it becomes open source, and people often make and distribute their own versions of it. For example, the operating system linux is open source, which is why people have made their own (free) versions of it.