[1] w3c/webappsec-fetch-metadata: WebAppSec has adopted sec-metadata as fetch-metadata (7/4/2019, 2:22:03 AM) https://github.com/w3c/webappsec-fetch-metadata/
[2] Fetch Metadata Request Headers (6/26/2019, 8:59:02 AM) https://www.w3.org/TR/2019/WD-fetch-metadata-20190627/
Google search: Sec-Fetch-*: