diff --git a/changelogs/client_server/newsfragments/1899.clarification b/changelogs/client_server/newsfragments/1899.clarification
new file mode 100644
index 00000000..6edeff05
--- /dev/null
+++ b/changelogs/client_server/newsfragments/1899.clarification
@@ -0,0 +1 @@
+Clarify that the fallback login page calls `window.matrixLogin.onLogin` instead of `window.onLogin`.