The _main.acl file is the first command file Arbortext Editor reads during startup. This file is located in the \packages subdirectory of Arbortext-path.

Because _main.acl is read early in the Arbortext Editor initialization, before any documents are opened, commands that manipulate menus (for example, menu_add and menu_move) are not valid in this file. Typically, the _main.acl file is maintained by a system administrator.