Registers an application name with the current AutoCAD drawing in preparation for using extended object data
(regapp application)
A string naming the application. The name must be a valid symbol table name. See the description of snvalid for the rules AutoLISP uses to determine if a symbol name is valid.
If an application of the same name has already been registered, this function returns nil; otherwise it returns the name of the application.
If registered successfully, the application name is entered into the APPID symbol table. This table maintains a list of the applications that are using extended data in the drawing.
(regapp "ADESK_4153322344")
(regapp "DESIGNER-v2.1-124753")