Mats Lewan wanted to be clear that the report was NOT leaked. He explains on his An Impossible Invention site how publication came about:
The report has been uploaded to Arxiv.org which, however has put it on hold, without specifying any motive for this. It has also been sent to Journal of Physics D. I got the report sent to me by Hanno Essén who said that he now considers it to be public, although not supposed to be published in any commercial journal until further notice from Journal of Physics.