diff --git a/doc/manual/rl-next/s3-sts-authentication.md b/doc/manual/rl-next/s3-sts-authentication.md
new file mode 100644
index 000000000..8dcc84c1b
--- /dev/null
+++ b/doc/manual/rl-next/s3-sts-authentication.md
@@ -0,0 +1,7 @@
+---
+synopsis: "C API: functions for locking and loading a flake"
+issues:
+prs: [12646]
+---
+
+Added support for STS-based authentication for S3-based binary caches, i.e. enabling seamless integration with `aws sso login`.