diff --git a/subprojects/gstreamer/docs/gst/running.md b/subprojects/gstreamer/docs/gst/running.md
index 65f5e6fd24..08eb86cc1d 100644
--- a/subprojects/gstreamer/docs/gst/running.md
+++ b/subprojects/gstreamer/docs/gst/running.md
@@ -268,7 +268,8 @@ Use `all` to enable all tracing flags.
 
 Set this variable to a file path to redirect all GStreamer debug
 messages to this file. If left unset, debug messages with be output unto
-the standard error.
+the standard error. The %p pattern is replaced with the PID and the %r
+with a random number.
 
 **`ORC_CODE`.**
 
diff --git a/subprojects/gstreamer/docs/index.md b/subprojects/gstreamer/docs/index.md
index 4237705e66..14b0450350 100644
--- a/subprojects/gstreamer/docs/index.md
+++ b/subprojects/gstreamer/docs/index.md
@@ -277,7 +277,9 @@ Use `all` to enable all tracing flags.
 
 Set this variable to a file path to redirect all GStreamer debug
 messages to this file. If left unset, debug messages with be output unto
-the standard error.
+the standard error. The %p pattern is replaced with the PID and the
+%r with a random number.
+
 
 **ORC_CODE.**