AutoHotkey_H development started around 2009 based on AutoHotkey_N created by tinku99 who introduced AutoHotkey.dll to allow real multi-threading (old forum).
Today AutoHotkey_H is much more than AutoHotkey.dll, it has many new features, compression and protection for compiled scripts, COM Interface and it is 99% compatible with main AutoHotkey.
The difference to main AutoHotkey is that #NoEnv is set by default and VarSetCapacity keeps memory in variable when capacity is changed.
Also AutoHotkey_H v2 based on AutoHotkey v2 is available and being developed.
Note that AutoHotkey_H documentation is only maintained for AutoHotkey v2 but most features are also available for AutoHotkey_H v1.
Downloads
Currently no installer is available, simply replace your AutoHotkey.exe with relevant AutoHotkey.exe from downloaded package and you are ready to go.
Compiler folder will need to be replaced as well if needed.
Copy AutoHotkey.exe to Compiler folder afterwards and rename it to Ahk2Exe.exe.
To compile ANSI version you will need the exe from Win32a and for Unicode from Win32w or x64w.
The password itself needs to be changed here, use you own fake entries. You can also have empty (\0) characters in between or use for example separate function to generate the password...
The best method is to generate the password dynamically through separate function(s) so it is not saved directly in source and that part of source code is not open to public!