How to unpack project.css.map and project.js.map and work on if there are no source files?

Question

css

I have a site from a previous developer.
There are files

/css/project.css
/css/project.css.map
/js/project.js
/js/project.js.map
The previous developer used sass for css. And used concatenation and compression to get project.js and project.css files.
Unfortunately, I don't have a /source/ folder where the js and sass source files were. But there are *.map files.
I don't know how these files were generated and compressed.
I can of course format the text in project.css and project.js and edit them however I want.
But before I start to break everything, there is a hope to unpack everything somehow, and continue to edit in the style as intended by the authors.
----------
Please tell me what was most likely the compression for css and js and whether it is possible to restore the original files based on the *.map files. Well, how to proceed with this.

Answer 1

There was a similar question discussed on StackOverflow . Try that script.
PS Unfortunately I can't check it myself.