Status Bar
When the document ends on page 30, and the page number is at the bottom of the page.
Maybe the number of the page?
Bottom center of page
Page numbers are typically placed at the top or bottom of a document, depending on the formatting style being used.
It will appear at the bottom of every page in the document.
on the bottom of the first page
The serial number on a travel document, such as a passport or visa, is typically located on the identification page or the data page. It is often printed in a machine-readable format at the bottom of the page or may be found near the personal information section. In passports, it is usually a combination of letters and numbers, while in visas, it may appear prominently at the top or bottom of the document. Always check the specific guidelines for the type of travel document you have, as the location can vary.
It is the Footer.
Footer
footnote
At the top and bottom of each page.
hard page break or manual page break