Update the SSO username picker template to comply with SIWA guidelines (#12210)

Fixes https://github.com/matrix-org/synapse/issues/12205

2 files changed, 12 insertions, 4 deletions

diff --git a/docs/sample_config.yaml b/docs/sample_config.yaml

index 6f3623c88a..ef25a3175f 100644
--- a/docs/sample_config.yaml
+++ b/docs/sample_config.yaml
@@ -1947,8 +1947,13 @@ saml2_config:
 #
 #             localpart_template: Jinja2 template for the localpart of the MXID.
 #                 If this is not set, the user will be prompted to choose their
-#                 own username (see 'sso_auth_account_details.html' in the 'sso'
-#                 section of this file).
+#                 own username (see the documentation for the
+#                 'sso_auth_account_details.html' template).
+#
+#             confirm_localpart: Whether to prompt the user to validate (or
+#                 change) the generated localpart (see the documentation for the
+#                 'sso_auth_account_details.html' template), instead of
+#                 registering the account right away.
 #
 #             display_name_template: Jinja2 template for the display name to set
 #                 on first login. If unset, no displayname will be set.
diff --git a/docs/templates.md b/docs/templates.md

index 2b66e9d862..b251d05cb9 100644
--- a/docs/templates.md
+++ b/docs/templates.md
@@ -176,8 +176,11 @@ Below are the templates Synapse will look for when generating pages related to S
              for the brand of the IdP
     * `user_attributes`: an object containing details about the user that
       we received from the IdP. May have the following attributes:
-        * display_name: the user's display_name
-        * emails: a list of email addresses
+        * `display_name`: the user's display name
+        * `emails`: a list of email addresses
+        * `localpart`: the local part of the Matrix user ID to register,
+          if `localpart_template` is set in the mapping provider configuration (empty
+          string if not)
   The template should render a form which submits the following fields:
     * `username`: the localpart of the user's chosen user id
 * `sso_new_user_consent.html`: HTML page allowing the user to consent to the