Manages the HTTP response headers of a website hosted on Opus Growth. mode = list (show the current headers), add (add or update the given fields), remove (delete the named fields) or replace (overwrite the whole set). headers = one 'Field: value' per line, optionally preceded by a path pattern to limit it to some paths (for example '/assets/* Cache-Control: public, max-age=31536000, immutable'; Cache-Control is accepted only with a path). Supported fields include Content-Security-Policy and its Report-Only variant, Reporting-Endpoints, Permissions-Policy, Referrer-Policy, the Cross-Origin policies, X-Frame-Options and Access-Control-Allow-Origin. Headers apply to the whole site and take effect within seconds. server and site select the target when there is more than one. confirm=false previews a change, confirm=true applies it.