So there's removing lines of code. But you can't get below zero that way. Whereas currently ohloh says that the Perl core has -14,194 lines of DOS batch script of which -1,394 are blank lines. [Is it a coincidence that this is language 13 :-)]. Negative blank lines - that's a neat trick on a neat trick.
That analysis is deemed "latest". I don't know how to link to it permanently. Whilst this seems to be a bug in ohloh, it may related to "Step 2 of 3: Importing source code into database (Failed)" and be fixed when they fix that.