[1] w3c/webappsec-fetch-metadata: WebAppSec has adopted sec-metadata as fetch-metadata (2019-07-04 11:22:03 +09:00) https://github.com/w3c/webappsec-fetch-metadata/
[2] Fetch Metadata Request Headers (2019-06-26 17:59:02 +09:00) https://www.w3.org/TR/2019/WD-fetch-metadata-20190627/