What could be the source of the following message contained in my log file?
Package hyperref Info: bookmark level for unknown unnumbered defaults to 0 on input line 48.
I should say that input line 48 and the lines before and after it only contain text, formulas and a blank line. There is a labelled equation environment but if I delete this, the message is still there (the label is the only thing which could possibly be connected with hyperref). I cannot reproduce the message if I compile these lines alone.