On that page, there is a link to another interesting page on the same site:

https://soc.me/interfaces/intels-original-64bit-extensions-f...

where there are links to a couple of patents filed by Intel in 2000, about a 64-bit extension of the x86 ISA, which had been implemented in Pentium 4, but which had been nonetheless disabled and hidden from the users, in order to not compete with Itanium.

The page explains the content of the patents.

As already mentioned by another poster, at least on Firefox you have to open a tab and then copy this link there, to avoid being identified as an "undesirable" :-)