With great sadness we learned yesterday of the peaceful passing of @gkellogg last Saturday.
In the last 14 years, as a W3C Invited Expert, Gregg co-edited 9 standards and a dozen other specs. He also implemented them all and contributed test suites that #w3c groups are still using.
His implication in the JSON-LD Working Group, that he co-chaired, was instrumental to the success of JSON-LD.
For all this, but also his friendliness and good nature, he will be dearly missed.

https://lists.w3.org/Archives/Public/semantic-web/2025Sep/0004.html