Hidden links (or something)

In my quest to find where my hidden links are, I've deleted every single sheet from my workbook (created new blank one), deleted all Defined names, confirmed there are no hidden sheets, etc.
With all this, I'm still seeing a link and my file STILL tried to connect upon opening.

Oddly enough, I couldn't attach the file because it's too big? with literally zero data entered on one black Sheet? How can a spreadsheet have nothing but a single empty sheet and still be 1.9mgs?

Any thoughts? So lost.