Why is Delphi (Zeos) giving me widestring fields in SQLite when I ask for unsigned big int?

I am using the latest Zeos with SQLite 3. It is generally going well, converting from MySQL, once we made all the persistent integer field TLargeInt.

But when we use a column definition "unsigned big int" (the only unsigned type allowed according to http://ift.tt/148oIVm), delphi is calling the resulting field a ftWidestring.

Any ideas?

TIA Mark