#include can be used to break out changes into separate, additional files. Inside each of those files, there can be other includes, which in turn can have other includes, and so on. The level of nesting allowed by the parser is 10. Beyond that System Architect will give a warning and ignore the subsequent levels.

For example, you could create three USRPROPS.TXT files, one for diagrams (arbitrarily named diagrams.txt), one for definitions (arbitrarily named definitions.txt), and one for symbols (arbitrarily named symbols.txt). The USRPROPS.TXT file would look like this:

Inside each of those files you could place #includes to other files, such as a file for lists (arbitrarily named lists.txt).

This command helps enable coherent reusability of user-defined data.