Weird/annoying text box attached to every cell in this excel file

Hi,

first of all, under no circumstances I do marketing for this web site. I find it rather annoying for the owner of this excel file to attach kind of comment to every single cell in this workbook. But I find it interesting and want to now how I can do that / remove that? You can see the text box in this picture. When I click on any cell, the textbox is displayed. The file is save as normal excel file (xlsx) without macros.

The excel file is here: [removed]

Thank you.