diff -r 1554bd50a1af -r b52f2b365eff mercurial/localrepo.py
--- a/mercurial/localrepo.py	Mon Dec 16 02:41:24 2024 -0500
+++ b/mercurial/localrepo.py	Mon Dec 16 03:04:44 2024 -0500
@@ -20,6 +20,7 @@
 from concurrent import futures
 from typing import (
     Optional,
+    Set,
 )
 
 from .i18n import _
@@ -341,7 +342,7 @@
 
     # Begin of ipeercapabilities interface.
 
-    def capabilities(self):
+    def capabilities(self) -> Set[bytes]:
         return self._caps
 
     # End of ipeercapabilities interface.