The link for the XMP-Prism spec (https://exiftool.org/TagNames/XMP.html#prism), http://www.prismstandard.org/, no longer works. Checking through the Internet Archive, it looks like the new link should be https://www.idealliance.org/prism-metadata
Bah, even that link is no good, as it links back prismstandard.org for the actual specs.
Maybe this is a proper link
https://www.w3.org/Submission/2020/SUBM-prism-20200910/prism-basic.html
I'll update this in the next release.
- Phil
I'm working on reviving those URLs and determining if the W3C publication is canonical. The former head of PRISM for Idealliance, Diane Kennedy, has retired. - J