diff --git a/docs/x509.rst b/docs/x509.rst
index 0ce9016..2e4a0ef 100644
--- a/docs/x509.rst
+++ b/docs/x509.rst
@@ -274,6 +274,9 @@
         :raises cryptography.x509.UnsupportedExtension: If the certificate
             contains an extension that is not supported.
 
+        :raises cryptography.x509.UnsupportedGeneralNameType: If an extension
+            contains a general name that is not supported.
+
         .. doctest::
 
             >>> for ext in cert.extensions:
@@ -969,6 +972,10 @@
     This is raised when a certificate contains an unsupported general name
     type in an extension.
 
+    .. attribute:: type
+
+        :type: :term:`text` or int
+
 
 .. _`public key infrastructure`: https://en.wikipedia.org/wiki/Public_key_infrastructure
 .. _`TLS`: https://en.wikipedia.org/wiki/Transport_Layer_Security