This puzzle is part of the Monthly Topic Challenge #14: Think inside the (very small) box!.
What is in the middle space?
The answer can be easily "read off" without computer assistance or special knowledge.
However, for the diehard puzzling enthusiasts, yes there is an optional secret message/hint hidden in the pixel ornamentation (THE extra dots and bars on the tAll nodes).
Although the question only asks about the middle one, each space holds a word. There is no cipher used, unless you are looking for a very helpful hint, in which case you should consult Samuel.
Seem hard? Reread everything. The way forward is hiding in plain sight. Also, web adventurer had the right idea to count things but I am not sure why they only counted some of the nodes.