diff --git a/src/bin/sage-update-version b/src/bin/sage-update-version
index 25e4c594798..d074347438c 100755
--- a/src/bin/sage-update-version
+++ b/src/bin/sage-update-version
@@ -54,7 +54,11 @@ EOF
 
 # Update Sage version file for shell scripts in SAGE_SRC/bin/sage-version.sh
 cat <<EOF > "$SAGE_SRC/bin/sage-version.sh"
-# Sage version information for shell scripts
+# Sage version information for shell scripts.
+#
+# #31049: The following line is valid shell code but not valid Python code,
+# which stops "setup.py develop" from rewriting it as a Python file.
+:
 # This file is auto-generated by the sage-update-version script, do not edit!
 SAGE_VERSION='$SAGE_VERSION'
 SAGE_RELEASE_DATE='$SAGE_RELEASE_DATE'
diff --git a/src/bin/sage-version.sh b/src/bin/sage-version.sh
index c66568933c0..33a79c5a046 100644
--- a/src/bin/sage-version.sh
+++ b/src/bin/sage-version.sh
@@ -1,4 +1,8 @@
-# Sage version information for shell scripts
+# Sage version information for shell scripts. The following line is valid shell code
+#
+# #31049: The following line is valid shell code but not valid Python code,
+# which stops "setup.py develop" from rewriting it as a Python file.
+:
 # This file is auto-generated by the sage-update-version script, do not edit!
 SAGE_VERSION='9.7.beta6'
 SAGE_RELEASE_DATE='2022-07-24'