From the author : 🙂

“The second tileable map package contains 6 normal, height and ambient occlusion maps as well as blend masks. Again the idea is to use those maps to create materials by using basic diffuse textures which you will usually find a lot of in UE3’s sample content. Contrary to the first package I changed the texture setup this time. Whilst all normal maps are stored in one 24bit .tga, ambient occlusion & height maps and blend masks are stored in just one 24bit .tga file using the red, green and blue channel separately.”

Official page 🙂