Thank you all for your interest. Doing my own research, I found something interesting.
It seems that this card is the materialisation of a common project conducted by Apple and TI in 1988, consisting on an Apple Macintosh II computer equipped with TI's Explorer Lisp coprocessor board and software environment. In other words, a lisp computer on a Macintosh... Very interesting, I never heard about that.
I've got one or two internet adresses, if anybody is interested in knowing a little bit more.