diff -r 968b29a5a7fc -r 5aafc3c5bdec mercurial/pycompat.py
--- a/mercurial/pycompat.py	Sun Feb 20 14:52:40 2022 -0700
+++ b/mercurial/pycompat.py	Sun Feb 20 15:03:26 2022 -0700
@@ -111,9 +111,6 @@
 sysexecutable = sys.executable
 if sysexecutable:
     sysexecutable = os.fsencode(sysexecutable)
-bytesio = io.BytesIO
-# TODO deprecate stringio name, as it is a lie on Python 3.
-stringio = bytesio
 
 
 def maplist(*args):