diff --git a/changelog.d/18906.misc b/changelog.d/18906.misc
new file mode 100644
index 00000000000..d7d8b47eb0c
--- /dev/null
+++ b/changelog.d/18906.misc
@@ -0,0 +1 @@
+Better explain how we manage the logcontext in `run_in_background(...)` and `run_as_background_process(...)`.
diff --git a/synapse/logging/context.py b/synapse/logging/context.py
index 6eaa19d2f6a..aa4b98e7c76 100644
--- a/synapse/logging/context.py
+++ b/synapse/logging/context.py
@@ -802,8 +802,9 @@ def run_in_background(
     deferred returned by the function completes.
 
     To explain how the log contexts work here:
-     - When this function is called, the current context is stored ("original"), we kick
-       off the background task, and we restore that original context before returning
+     - When `run_in_background` is called, the current context is stored ("original"),
+       we kick off the background task in the current context, and we restore that
+       original context before returning
      - When the background task finishes, we don't want to leak our context into the
        reactor which would erroneously get attached to the next operation picked up by
        the event loop. We add a callback to the deferred which will clear the logging
@@ -828,6 +829,7 @@ def run_in_background(
     """
     calling_context = current_context()
     try:
+        # (kick off the task in the current context)
         res = f(*args, **kwargs)
     except Exception:
         # the assumption here is that the caller doesn't want to be disturbed
diff --git a/synapse/metrics/background_process_metrics.py b/synapse/metrics/background_process_metrics.py
index c6ee21d42aa..633705b02a3 100644
--- a/synapse/metrics/background_process_metrics.py
+++ b/synapse/metrics/background_process_metrics.py
@@ -286,9 +286,11 @@ async def run() -> Optional[R]:
                 ).dec()
 
     # To explain how the log contexts work here:
-    #  - When this function is called, the current context is stored (using
-    #    `PreserveLoggingContext`), we kick off the background task, and we restore the
-    #    original context before returning (also part of `PreserveLoggingContext`).
+    #  - When `run_as_background_process` is called, the current context is stored
+    #    (using `PreserveLoggingContext`), we kick off the background task, and we
+    #    restore the original context before returning (also part of
+    #    `PreserveLoggingContext`).
+    #  - The background task runs in its own new logcontext named after `desc`
     #  - When the background task finishes, we don't want to leak our background context
     #    into the reactor which would erroneously get attached to the next operation
     #    picked up by the event loop. We use `PreserveLoggingContext` to set the