Conclusion

Your full LevelZ file should look something like this:

@type 2
@spawn [0, 0]
@mycustomheader myvalue
---
grass: [0, 0]*[0, 1]
{stone, grass}: [1, 0]*[1, 1]
end

End Keyword

Each LevelZ file can optionally end with an end keyword at the end. This signals that the parser should stop reading the file and use all the information it has currently read.

@type 2
@spawn [5, 0]
---
grass: [0, 0]
stone: [0, 1]*[-1, 2]

Comments

Because parsers (should) stop after reading an end keyword in the Block section, you can insert whatever you want after the end keyword. This is the official way to declare comments in LevelZ files.

@type 3
@spawn [1, 1, 4]
---
grass: (0, 10, 0, 0, 0, 10)^[0, 0, 0]
end

Wrote a simple grass platform over here. Looks pretty good.