Since Tuner-Express uses a "definition file" to describe what is shown to the user, both the data file (.bin, etc) and a definition file (.vdt, ect) must be loaded. The auto load rules allows any number of definition files to be loaded upon opening a data file. For example if all your obd0 honda development files contain the string "ng64", you can assign those files to automatically open the ng development definition. Also, if you keep all of your stock rom's in a certain location (ie. folder), any data file residing in that folder can be assigned to utilize a certain definition file.
The following is an example of how to utilize the rules.
Go to File>Auto Load Rules...
In the Auto Load dialog, you have the ability to add (or delete) as many rows as required using the mouse right click menu. As shown in the image below: The Data File column is used to select a comparison (ie. if your data file location equals, begins with, etc) while the Text column is what the software is comparing against. The button column labeled ... allows you to select what handler to utilize if the comparison is true. Handler Path column shows the currently assigned definition file.

Note that the comparison routine is order sensitive. The first row to test True will be utilized; buttons to the right-side of the dialog allow for Row ordering as well as saving of the Auto Load Rules.
In the future, the ability to make a single file that combines the data file and it's definition may be added.