That's not "quite a bit", it's "a bit". Here's what it says, summarized:
These let you play copied games. There are 20-pin models, 21-pin models, and models with connectors for both. They go between the CD board and the main board. Here are 3 pics that are just barely crappy enough that the chip markings are unreadable. Here's two outdated links to places that might sell them.