GEO_BI2010 (V101_BI2010) indicates the region of Burundi where the respondent was interviewed. DHS regions in the 2010 Burundi survey are equivalent to divisions.
Other sample years have their own sample-specific geography variables. There is also an integrated variable, GEO_BI2010_2016, that provides spatially consistent units over time.
A GIS map for GEO_BI2010 (in shapefile format) can be downloaded from the DHS Program Spatial Data Repository [URL omitted from DDI.] Boundaries page.