The Env Info file has the following foramt:

n width, m height. The size of the grid of n x m.

The following is an example of a 4 x 4 grid 4,4
S-7-
X--X
-2--
-3G-

The key is:

[1..9] are dirtiness digits.
'-' is an empty cell.
'X' is an impassable cell, the agent cannot go here.
'S' is the start position, default is 0,0 ( the top left corner ).
'G' is the goal to the agent is to traverse to.

File name format: ".env". I have all of the files in the env folder.