Compose the hreflang annotation for a multilingual page, as <head> link tags and HTTP header Link lines.
The page you are annotating. One of the translation rows below must point back to this exact URL.
Codes: two-letter language, optionally a two-letter region (e.g. en, en-us, fr, es-419). x-default is allowed at most once. Row URL fields also accept es-419-style regions with digits.
<link rel="alternate"> tagsLink: headersLink: header per line. In Nginx/Apache send each as its own Link: header; CDNs like Cloudflare accept the raw lines verbatim.