1 files changed, 15 insertions, 0 deletions
diff --git a/transport-helper.c b/transport-helper.c
index 61c928f6cd..cfe0988490 100644
--- a/transport-helper.c
+++ b/transport-helper.c
@@ -444,6 +444,21 @@ static int fetch_with_import(struct transport *transport,
 	free(fastimport.argv);
 	fastimport.argv = NULL;
 
+	/*
+	 * The fast-import stream of a remote helper that advertises
+	 * the "refspec" capability writes to the refs named after the
+	 * right hand side of the first refspec matching each ref we
+	 * were fetching.
+	 *
+	 * (If no "refspec" capability was specified, for historical
+	 * reasons we default to *:*.)
+	 *
+	 * Store the result in to_fetch[i].old_sha1.  Callers such
+	 * as "git fetch" can use the value to write feedback to the
+	 * terminal, populate FETCH_HEAD, and determine what new value
+	 * should be written to peer_ref if the update is a
+	 * fast-forward or this is a forced update.
+	 */
 	for (i = 0; i < nr_heads; i++) {
 		char *private;
 		posn = to_fetch[i];