The MTA Ingame Handling Editor (shortly hedit or ahe) is an open source resource being developed for the latest version of MTA.
You can see and download the latest version on the GitHub repository.
The current version is 2.1. Version 3 is currently being worked on and is a complete rewrite of the system.
GitHub repository - See and get the latest changes here. Look at the upcoming 3.0 edition.
Official Forum Topic - The place for discussing this project.
Youtube playlist - Full playlist of all development video's of the handling editor.