If you're interested in learning more or accessing the PDF document, I recommend visiting the PCI-SIG website (pci-sig.com) or searching for the document title directly.
You're looking for information on the PCI Express M.2 specification, specifically revision 5.0, version 1.0. Here's what I found:
The M.2 specification is a standard for small, high-speed expansion cards used in computers. It's a widely adopted standard for adding peripherals like Wi-Fi, Bluetooth, and storage to devices.