Field list question

[eskyline]

What is the significance of this field?  The icon is not that of a measure or calculated column.  Inclusion of this field also seems to impact aggregation in charts.  This is from a VSO content pack so we don't have visibility into the dataset.

[greggyb]

It marks the field as a row identifier for a given table. Currently I don't think this functionality is exposed in the Power BI UI, but if importing a model from Excel or consuming a Tabular model, this attribute can be marked. When used in a visual, this sort of field will always default to being a label / category / axis, rather than having a default aggregation.