kovidgoyal/calibre — pull request #176 by sengian (2014-02-13 21:45:40+00:00)
Title: Pdf meta improve for DOI, arXiv, PMCID retrieval

Basically some parsing to help with professional scientific literature.

One thing I saw which is surprising for me is that you add to an existing title an 'Unknown' string if metadata are retrieved from the pdf.