МОД: Клинок Армагеддона / Armageddon's Blade

But it's only 1 KB

I can't replace 29 KB with 1 KB.

Take the index file, which is 29 KB, put it into the map, open the map, create a model, save the map, go to this path, and take the ready-made index for your mod.

Added 29 minutes later
By the way, I figured out Unpack and Pack – it seems they were intended not for maps, but for working with other files. That's why the screen remains black. When you open a map this way, you start working with it as with a mod. That is, if you create a model or a series of models or something else and pack the mod, the index file will remain in the mod so that next time you open it, you can easily find these models in the list.

Added 6 minutes later
[/U]Then you need to do it this way:
Take a map, put the index from data.pak into it, open it with the button, unpack the MOD, create a model, save it with the pack MOD button, and extract the new index file from the map