Dev:Substitute

From The Apple Wiki

Substitute is a system for modifying code at runtime by substituting custom implementations for arbitrary functions and Objective-C methods. It is also a Free Software (& open-source) substitute for Cydia Substrate.

The library is used in the Electra jailbreak.

Substitute was originally made by comex on 8 January 2015, but CoolStar has since taken over the project sometime in January 2018.