Hi Yoni,
I understand that you want to have a .gri file that you want to open in Matlab.
Have you considered the Import Tool app? (Home Tab > Variable section > Import Data)
With the file you provided, Import Tool is showing all the data in the file in a neat grid. If you’re happy with this data, you may import the contents as an array, a cell array, a table etc. For more information, see the documentation on Import Tool below.
Hope it Helps!