excerpt from SE's Help:
From Active Document %{Mass}
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Specifies that property values are retrieved from the active file.
Named Reference %{Mass|<file name}
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Specifies that property values are retrieved from the reference file currently
highlighted in Parts.
Index Reference %{Mass|Rx}
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Specifies that property values are retrieved from the history-based index of
model files inserted into the drawing. You can see the sequence of inserted
files in Parts.
Index Reference provides access to top-level assembly information.
From Graphic Connection %{Mass|G}
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Specifies that the property values are retrieved from one of the following:
- If the annotation is connected to a part in a subassembly, information is
retrieved from the subassembly.
- If the annotation is connected to a part in a top-level assembly, it
displays information from the part.
From Graphic Connection provides access to top-level assembly information.
In assembly documents, it retrieves property values from the top-level occurrence, whether the occurrence is an assembly or a part file.
From Graphic Connection to Part %{Mass|GP}
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Specifies that property values are retrieved from the part the
annotation is connected to.
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