What is Project Support Material in GTD?
Project Support Material
It is relevant information for your projects.
The Project List is just an index. All of the details, plans, and supporting information that you may need as you work on your various projects should be contained in separate file folders, computer files, notebooks, binders, etc.
The project support material is almost identical to the general reference material, and could be kept in the same file system. The main difference is that you will need to check the support material on a more consistent basis and therefore you will want to have it more handy.