Thanks a lot for the answers.
The 2da files in NWN2 are just table files (imagine excel), where information about stuff is stored. For example feat.2da contains information about the feats. Which icon they have, which bonus they give if any, and a reference to a tlk file.
The tlk file is also a table file with just text. For example the row referenced by the feat.2da will contain the name of the feat and its description.
So basically, we used them to add things to the game like feats, placeables etc.
