From 32b0eafdb33c3a162eaaf96f5a97907cc5706fe4 Mon Sep 17 00:00:00 2001
From: Erik Johnston <erik@matrix.org>
Date: Mon, 22 Jun 2026 11:01:58 +0100
Subject: [PATCH] Comment on what transaction IDs are

---
 rust/src/events/internal_metadata.rs | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/rust/src/events/internal_metadata.rs b/rust/src/events/internal_metadata.rs
index fa77f5df25..0778fbfeaa 100644
--- a/rust/src/events/internal_metadata.rs
+++ b/rust/src/events/internal_metadata.rs
@@ -505,6 +505,9 @@ impl EventInternalMetadata {
     }
 
     /// The transaction ID, if set when the event was created.
+    ///
+    /// The transaction ID comes from the `txn_id` path parameter of the
+    /// client-server API request used to send the event.
     pub fn txn_id(&self) -> PyResult<Option<String>> {
         Ok(self.read_inner()?.get_txn_id().map(|s| s.to_owned()))
     }