The makelocalealias.py ignores UTF-8 mapping. Expected that this encoding is available for all locales. After enabling UTF-8 mapping in makelocalealias.py most aliases are optimized out except following:

+    'be_bg.utf8':                           'bg_BG.UTF-8',
+    'c.utf8':                               'en_US.UTF-8',
+    'en_dl.utf8':                           'en_DL.UTF-8',
+    'en_zw.utf8':                           'en_ZS.UTF-8',
+    'ks_in@devanagari.utf8':                'ks_IN.UTF-8@devanagari',
+    'pa_pk.utf8':                           'pa_PK.UTF-8',
+    'sd_in@devanagari.utf8':                'sd_IN.UTF-8@devanagari',
+    'sr_yu.utf8':                           'sr_RS.UTF-8',
+    'sr_yu.utf8@cyrillic':                  'sr_RS.UTF-8',
+    'te_in.utf8':                           'te_IN.UTF-8',
+    'zh_sg.utf8':                           'zh_SG.UTF-8',

Some of them maps to other country (en_zw.utf8 to en_ZS.UTF-8, sr_yu.utf8 to sr_RS.UTF-8) and these mappings are different from base mappings (en_zw to en_ZW.ISO8859-1, sr_yu to sr_RS.UTF-8@latin). The devanagari mappings just maps illformed locales. c.utf8 is yet one special case. Other mappings have no base entity without encoding.

Here is a patch which enables UTF-8 mapping in makelocalealias.py and adds all these mappings to locale alias table.