"I'll tell you a secret: all the characteristics of units/equipment/weapons are stored in easy-to-read Excel files in the game, you can edit these files and these changes will be applied in the game.
IT'S SO SIMPLE!

In the root of the game you need to open the “basis.pak” file using an archiver such as WINRAR. (password: “oKoo$]bnGTKJLMNBA9A”), copy the basis.pak/scripts/species folder to yourself separately, inside the “species” folder you will find all the characteristics of everything that is in the game.

How to edit:
For convenience, change the file extension to .XLS (for example tanks.xml -> tanks.XLS).
Now the file can be easily opened in Excel, for example, find “Fnd_abrams” in the first column and moving along the line to the right, look for the “supply_consumption” column, change “5500” to .... for example “500”, okay, now the daily cost of maintaining the abrams tank is only 500. Similarly, you can change any value, including for cars (cars.xml), helicopters (helicopters.xml), units (squads.xls) and so on.

In the “exp_levels.xml” file you can change the required amount of experience for leveling up units.

IMPORTANT !!!
How to save changes and add to the game:
After editing the files themselves, you simply save and return the original file extension .xml
BUT! DO NOT ADD CHANGED FILES to “basis.pak” or overwrite the original files.
You need to put the modified files in a similar path to the appropriate subfolder of the game (there is a folder in the root of the game called basis, you need to create the missing subfolders “scripts”\”species”). Modified files in these folders will take precedence over the original files.

P.S.
Watch the introductory video CAREFULLY. In the first seconds, sets of numbers appear, try googling them, it will surprise you ;) "

Please check the thread for more info, and updated links as people continue figuring out how to modify this excellent game.