This control is set by the projectdoc Toolbox on document properties imported from other projectdoc documents by the use of the the Document Properties Supplier From Documents Macro.

Typically this is an internal marker and not used in documentation work. However, this control is exported via the Web API and therefore part of the projectdoc Toolbox API.

In case the importing macro has an identifier, this identifier is provided with an additional control. For instance if the identifier is config, the additional control is named supplied:config.

Note that imported properties are automatically importable by other documents.