Could this be part of "för- och eftersätts[blad]" which would refer to the front and back flyleaves in the binding of a book? Perhaps the "blad" has been simply "understood".

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Note added at 2 days3 hrs (2007-01-27 23:42:44 GMT)
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Flyleaf being the blank sheet of paper you end up with - back or front - because the writing when typeset runs to a number of pages which isn't divisible by four (when you consider how a book or pamphlet is bound - A4 folding once to A5 etc. or compilations of them) and the publishers want the title or opening text to appear on the right hand page.

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Note added at 2 days3 hrs (2007-01-27 23:53:54 GMT)
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Equally, if the printers have to insert a "leaf" (= four pages when bound) to correct this, this becomes extra space to print on (inside title page, dedications etc). That would explain the "tryck" in your original. Also a lot of publishers like the end of the publication to occur on a left hand page, so there could be more than one flyleaf either side of the main body.