diff -r 1554bd50a1af -r b52f2b365eff mercurial/interfaces/repository.py
--- a/mercurial/interfaces/repository.py	Mon Dec 16 02:41:24 2024 -0500
+++ b/mercurial/interfaces/repository.py	Mon Dec 16 03:04:44 2024 -0500
@@ -205,7 +205,7 @@
         """
 
     @abc.abstractmethod
-    def capabilities(self):
+    def capabilities(self) -> Set[bytes]:
         """Obtain capabilities of the peer.
 
         Returns a set of string capabilities.