On Debian testing, I get a few changes that look like fixes but not es_CU yet:

@@ -807,0 +818,1 @@ locale_alias = {
+    'bokm\xef\xbf\xbd':                     'nb_NO.ISO8859-1',
@@ -822,0 +834,1 @@ locale_alias = {
+    'c.ascii':                              'C',
@@ -936,0 +949,3 @@ locale_alias = {
+    'en_dk':                                'en_DK.ISO8859-1',
+    'en_dk.iso88591':                       'en_DK.ISO8859-1',
+    'en_dk.iso885915':                      'en_DK.ISO8859-15',
@@ -976,1 +991,1 @@ locale_alias = {
-    'english.iso88591':                     'en_EN.ISO8859-1',
+    'english.iso88591':                     'en_US.ISO8859-1',
@@ -1114,0 +1130,1 @@ locale_alias = {
+    'fran\xef\xbf\xbdis':                   'fr_FR.ISO8859-1',
@@ -1164,2 +1180,2 @@ locale_alias = {
-    'hebrew':                               'iw_IL.ISO8859-8',
-    'hebrew.iso88598':                      'iw_IL.ISO8859-8',
+    'hebrew':                               'he_IL.ISO8859-8',
+    'hebrew.iso88598':                      'he_IL.ISO8859-8',
@@ -1246,0 +1263,1 @@ locale_alias = {
+    'km':                                   'km_KH.UTF-8',
@@ -1413,1 +1430,1 @@ locale_alias = {
-    'russian':                              'ru_RU.ISO8859-5',
+    'russian':                              'ru_RU.KOI8-R',
@@ -1427,0 +1445,1 @@ locale_alias = {
+    'sid_et':                               'sid_ET.UTF-8',

I could hunt down the very latest upstream X.org locale.alias file and try the script again.  And/or we can do this one addition (es_CU) now, unless there are issues with Python recognizing a locale that the OS doesn’t know about yet.


MAL: the script needed no change at all to find the file and run! :)  We could make it more similar to token/keyword/etc and have it update locale.py in 3.4+.  Also maybe make updating the aliases a part of feature release workflow, or even bugfix releases.