A Bosch MAF sensor from a 1994-1996 Volvo looks like this:
I have read about different types of these old sensors and they all mention a "wire", however I cannot see a wire in this sensor, just a board and two vanes. What kind of sensor is it?
The Bosch MAF you have is most likely a hot film and not a hot wire sensor. Both the hot wire and hot film versions can function in the same way, in that they register the cooling as a voltage change, which then registers as the mass of air being drawn into the system. Hot film MAFs can also send a frequency to the computer to calculate the amount of air, though I don't believe this is the way your Volvo one works.
You can read about hot wire/film MAFs on the wikipedia page.