i was a subscriber for ST Format for many years and also had many other magazines... alas, when i divorced, i was unable to bring most of my Atari stuff with me...
i´m willing to donate some money to help with shipping costs, but maybe a scanner would be cheaper to buy than shipping a whole collection of magazines from one place to the other...?
if another person has a different whole collection, then it would only be necessary to ship the scanner, for example... just a thought...
Sorry, i was thinking better and it's both too small to be an accelerator card, nor it seems to suppose to fit a 6800 CPU.
Check if the STe has a 1.44Mb floppy, i think they needed to work in 16mhz to read high density discs. The female could have had a 'stick' to change between 8mhz and 16mhz.
28 pins could be right for the floppy controller.
It would to know to wich chip it was plugged.