You're welcome ;).
There are a few algorithms for noises, Perlin and Simplex are two of them, I guess there is no need to fully understand everything behind for using them, and implement them may not be too hard to do if no one already done for the language you use, in C++ there is quite a huge probability some already exists.
It was in fact not fully debugging tool, then numbers are just to have a quick view of what was generated, then replaced by tiles gfx, it become a nice world to play on like below when it is partially done:
here with some "developer's assets".
The strength of using noise allow to have an actually infinite worlds with very tiny memory footprint as the same seed generate the same map and "moving" is just generate a new map with a little shift in each step to one direction.
I guess this is experience talking, as a professional software engineer, I did lot's of such small step to move forward with the least possible issues (it's like building a house, starting by foundations which have to be strong) and I'm always interested by making game but never really get fully committed to I've only started doing some core stuff, until now maybe, Godot is very great tool and simplify a lot's of annoying low-value work.