+.new
+The file(s) should be in DER format,
+except for GnuTLS 3.6.3 or later when an optional filetype prefix
+can be used. The prefix must be one of "DER" or "PEM", followed by
+a single space. If one is used it sets the format for subsequent
+files in the list; the initial format is DER.
+When a PEM format file is used it may contain multiple proofs,
+for multiple certificate chain element proofs under TLS1.3.
+.wen