@benjaminp, when you run Tools/i18n/makelocalealias.py on unmodified sources, you get also a list of modified aliases:

#    updated 'az_az' -> 'az_AZ.ISO8859-9E' to 'az_AZ.UTF-8'
#    updated 'ca_ad' -> 'ca_AD.ISO8859-1' to 'ca_AD.ISO8859-15'
#    updated 'ca_fr' -> 'ca_FR.ISO8859-1' to 'ca_FR.ISO8859-15'

It should be added to the long comment before the alias table. Only "updated" lines are needed, not "removed".

Add a comment that glibc aliases now are preferred. This is the main cause of changes.

And please add a test for en_IN.