2.1.1271 Part 1 Section 18.104.22.168, ext (Extents)
For additional notes that apply to this portion of the standard, please see the notes for ext, §22.214.171.124(a) .
a. The standard states that the ext element specifies the size of the bounding box enclosing the referenced object.
In Office, the extents also determine the size and center of the object for most geometry definitions. If the geometry data is independent of these extents, they are only used to determine the center for rotation and flipping.