2.1.28 [ISO32000-1] Section 12.4.2, Page Labels

V0028:

The specification states:

 Each page in a PDF document shall be identified by an integer page index that expresses the page’s relative position within the document. In addition, a document may optionally define page labels (PDF 1.3) to identify each page visually on the screen or in print.

Microsoft Edge:

Page labels are not supported (their presence is ignored).