— -- you could use links to do what you are trying to do.
For example:
- export initial project (first time export)
- open initial project in the XDK
- export second time to a new location (preserving state of first export)
- replace www in first project (the active XDK project) with a link to the second project's www folder
- make subsequent exports to the second project
Now all subsequent updates from C2 go to the second location and only the www folder in your initial XDK project will be updated, leaving the <project-name>.xdk unchanged each time you export to the second project.
In this case your first project is the master XDK project, meaning it contains the plugins folder, the <project-name>.xdk file, etc. The second project is the master source code project, because it contains the www folder with all resources. This will work best with hard links, not soft links, which require that both projects exist on the same filesystem. Hard links are supported on Mac, Linux and Windows machines, so this solution applies regardless of the OS on your development system.