On a freshly installed page, there is no InterWikiMap page. When the user comes to edit it, there is no indication about its proper syntax.

I propose shipping a default InterWikiMap file with MoinMoin, containing something like this:

{{{
#format plain
#
# Add InterWiki entries, one per line, in the following format:
#
#  name url
# 
# for instance:
# 
#  google http://google.com/search?q=
#  UPC http://www.upcdatabase.com/item/
}}}

[[http://master19.moinmo.in/4ct10n/CheckTranslation/InterWikiMap?action=CheckTranslation&pageset=not_translated_system_pages&language=en| implemented in 1.9]]
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CategoryFeatureImplemented