GRASS program details
Get familiar with the list of file extensions supported by GRASS. By means of the mentioned application you will be able to perform at least the basic operations related with the listed files, such us opening, change or saving the file.
If you want to download GRASS, you can use the link "Visit the website". The address leads to the producer of GRASS. Such a trusted website is the safest and the most trusted source allowing to download the files for installation of GRASS.