From 725d0df90de0e8b7b94e7f91cfb81713ebed326a Mon Sep 17 00:00:00 2001
From: Paul Eggert <eggert@cs.ucla.edu>
Date: Mon, 14 Jun 2021 00:04:02 -0700
Subject: [PROPOSED] New guideline against further merging

* theory.html (Timezone identifiers): Guide against further
merging of timezones merely because they agree since 1970.
* NEWS: Mention this.
---
 NEWS        | 3 +++
 theory.html | 5 +++++
 2 files changed, 8 insertions(+)

diff --git a/NEWS b/NEWS
index 53890a7..47bc632 100644
--- a/NEWS
+++ b/NEWS
@@ -50,6 +50,9 @@ Unreleased, experimental changes
 
   Changes to maintenance procedure
 
+    Add a guideline against further timezone merges, so that the
+    merges in this release are the last such merges.
+
     The new file SECURITY covers how to report security-related bugs.
 
     Several backward-compatibility links have been moved to the
diff --git a/theory.html b/theory.html
index 5a05f4b..9498d0b 100644
--- a/theory.html
+++ b/theory.html
@@ -224,6 +224,11 @@ in decreasing order of importance:
     even if some of the clocks disagreed before 1970.
     Otherwise these tables would become annoyingly large.
   </li>
+  <li>
+    Do not merge already-existing timezones merely because their
+    clocks have agreed since 1970.  This helps avoid data churn for
+    timezones created before the preceding guideline was in place.
+  </li>
   <li>
     If boundaries between regions are fluid, such as during a war or
     insurrection, do not bother to create a new timezone merely
-- 
2.30.2

