diff -r 9b51a4fb0f96 -r f610d705c3ca mercurial/bundlecaches.py
--- a/mercurial/bundlecaches.py	Tue Apr 09 14:37:24 2024 +0200
+++ b/mercurial/bundlecaches.py	Tue Apr 09 14:41:48 2024 +0200
@@ -160,8 +160,6 @@
 }
 _bundlespeccontentopts[b'bundle2'] = _bundlespeccontentopts[b'v2']
 
-_bundlespecvariants = {b"streamv2": {}}
-
 # Compression engines allowed in version 1. THIS SHOULD NEVER CHANGE.
 _bundlespecv1compengines = {b'gzip', b'bzip2', b'none'}