<pre> [[BR]]? is used to insert a line break (<br/>)
Probably it is not supported yet because it is a socalled Macro: http://moinmoin.wikiwikiweb.de/HelpOnMacros#head-734ab035917c8a1abee0a9b1af803096ebf5a3a6
Anyway, it is wiki tag, which is not unimportant
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