https://datatracker.ietf.org/doc/html/draft-ietf-core-link-format-07
draft-ietf-core-link-format-07
Constrained RESTful Environments (CoRE) Link Format (Internet-Draft, 2011)
core linkdraftietfformat
https://techcommunity.microsoft.com/discussions/sharepoint_general/page-viewer-web-part-file-link-format/3871815
Page Viewer Web Part File Link Format | Microsoft Community Hub
Struggling to insert the value acceptable to the Page Viewer web part Link property. It's a PDF in Site Assets doc lib, and that PDF may be switched in and...
part filelink formatmicrosoft communityviewerweb