Simple as the title suggest really. Reaper currently stores all of it's start-up settings in a handful of ini files. This feature would allow the user to export all of the data in these files to one consolidated file and import it to other systems whenever necessary.
The following actions/button/menu options would be created:
Export current ReaConfiguration to file
Save current ReaConfiguration as default
The way it would work would be pretty straightforward. Exporting the ReaConfiguration would write the preferences, keymap, theme and menus/toolbars to a consolidated ini file. When importing, the user would be presented with a dialog with checkboxes for each of the following options:
This way, you could specify which elements of the ReaConfiguration you want to load and which you want to remain untouched.
These settings would not override the user defaults permanently, only immediately after loading them and until quitting REAPER. Upon next REAPER start up, it would read it's preferences from the .ini files that already exist in the resource folder that are based on the user's own settings, not the settings loaded from the ReaConfiguration. This is where "Save current ReaConfiguration as default" comes in. This would allow you to take whatever configuration you are currently using and write it to the existing separate ini files so that Reaper would remember those settings from start up.
This would make it very simple for people to share entire REAPER configurations to test out different workflows. You could simply export your ReaConfiguration, send it to someone, and they could load it up and check it out, without making any permanent alterations to their personal configuration.