/.well-known/
Well-known resources go in here. (Thanks, Mark.)
did.json— this file defines the DIDdid:web:tess.oconnor.cx.gpc.json— a file which declares that this site complies with GPC requests.
Legacy well-known resources often live elsewhere.
/favicon.ico— a favicon is a little icon that browsers display in tabs and in the location bar./robots.txt— a file which defines what parts of a site web crawlers are allowed to crawl./sitemap.xml— a sitemap is a file, ingested by search engines, that lists every URL on a site.