I think exportnowrap is busted
$ w3m -no-proxy -dump "http://test.wikipedia.org/w/api.php?action=query&titles=Main%20Page&export"|wc
127 530 8475
$ w3m -no-proxy -dump "http://test.wikipedia.org/w/api.php?action=query&titles=Main%20Page&exportnowrap"|wc
23 49 914
$ GET "http://test.wikipedia.org/w/index.php?title=Main%20Page&action=raw"|wc
37 319 2950
Version: 1.15.x
Severity: trivial
http://test.wikipedia.org/w/api.php?action=query&titles=Main%20Page&exportnowrap
Internal error in ApiFormatRaw::getMimeType: No MIME type set for raw formatter
Backtrace:
#0 /home/wikipedia/common/php-1.5/includes/api/ApiBase.php(846): wfDebugDieBacktrace('Internal error ...')
#1 /home/wikipedia/common/php-1.5/includes/api/ApiFormatRaw.php(44): ApiBase::dieDebug('ApiFormatRaw::g...', 'No MIME type se...')
#2 /home/wikipedia/common/php-1.5/includes/api/ApiFormatBase.php(112): ApiFormatRaw->getMimeType()
#3 /home/wikipedia/common/php-1.5/includes/api/ApiMain.php(455): ApiFormatBase->initPrinter(true)
#4 /home/wikipedia/common/php-1.5/includes/api/ApiMain.php(290): ApiMain->printResult(true)
#5 /home/wikipedia/common/php-1.5/includes/api/ApiMain.php(245): ApiMain->executeActionWithErrorHandling()
#6 /home/wikipedia/common/php-1.5/api.php(77): ApiMain->execute()
#7 /usr/local/apache/common-local/live-1.5/api.php(3): require('/home/wikipedia...')
#8 {main}
Was reported earlier and fixed on trunk 3 weeks ago (!), but the fix hasn't gone live yet, which is quite worrying (scap, Brion, scap!)
Also note that this is an incorrect use of &exportnowrap: both &export and &exportnowrap must be used. The api.php documentation was updated to mention this in the same revision.