--- seamonkey-2.53.15/modules/libpref/init/all.js.orig	2023-01-27 18:29:34.423121884 +0300
+++ seamonkey-2.53.15/modules/libpref/init/all.js	2023-01-27 18:30:41.652359275 +0300
@@ -2506,6 +2506,7 @@
 pref("intl.charset.fallback.tld",           true);
 pref("intl.charset.fallback.utf8_for_file", false);
 pref("intl.ellipsis",                       "chrome://global-platform/locale/intl.properties");
+pref("intl.locale.matchOS",                 true);
 // this pref allows user to request that all internationalization formatters
 // like date/time formatting, unit formatting, calendars etc. should use
 // OS locale set instead of the app locale set.