If a cell contains a formula its .Tokens property is a non-empty array (sequence).
If the formula contains a reference, the respective token has .OpCode 0 and .Data which is in the simple case a structure of type com.sun.star.sheet.SingleReference. This structure holds a property .Flags telling mainly which parts of the reference should be treated as relative, if the tokens are moved(copied) to a different cell. The flags are additive and should be explained here.
I don’t understand the flag 64 which is named SHEET_3D and for which the more information doesn’t tell anything reasonable.
My experiments seem to show that this flag must be set if the resulting formula shall have an explicit sheet part at all.
Please explain this to me.