what is this? Does this mean that we need to be careful about number od TAB signs like in pyhton? This is rally painful … imagine what pain would cause this if you want to write a shell configuration script. or when you want to debug. Ppl from Ubuntu didnt need this… it is a shame 
It’s YAML format. This is widely used and you should be able to find plenty of information on it.
Tabs for indentation are banned in YAML for exactly the reasons you say, so there should be no problem here. If you’re using vim, you can :set et to make sure that pressing tab results in the matching spaces to be inserted instead.
I’ve moved this to the https://community.ubuntu.com/c/support-help-requests category because this site isn’t designed to take tech support questions. Sorry. I’d recommend using one of the official support channels listed on the https://community.ubuntu.com/t/finding-help/712 page