diff --git a/changelog.d/18420.misc b/changelog.d/18420.misc
new file mode 100644
index 0000000000..d52175af91
--- /dev/null
+++ b/changelog.d/18420.misc
@@ -0,0 +1 @@
+Explain why we `flush_buffer()` for Python `print(...)` output.
diff --git a/docker/configure_workers_and_start.py b/docker/configure_workers_and_start.py
index df34d51f77..102a88fad1 100755
--- a/docker/configure_workers_and_start.py
+++ b/docker/configure_workers_and_start.py
@@ -352,6 +352,11 @@ def error(txt: str) -> NoReturn:
 
 
 def flush_buffers() -> None:
+    """
+    Python's `print()` buffers output by default, typically waiting until ~8KB
+    accumulates. This method can be used to flush the buffers so we can see the output
+    of any print statements so far.
+    """
     sys.stdout.flush()
     sys.stderr.flush()
 
diff --git a/docker/start.py b/docker/start.py
index 818a5355ca..0be9976a0c 100755
--- a/docker/start.py
+++ b/docker/start.py
@@ -22,6 +22,11 @@ def error(txt: str) -> NoReturn:
 
 
 def flush_buffers() -> None:
+    """
+    Python's `print()` buffers output by default, typically waiting until ~8KB
+    accumulates. This method can be used to flush the buffers so we can see the output
+    of any print statements so far.
+    """
     sys.stdout.flush()
     sys.stderr.flush()