Understanding the File Structure of Bootstrap

if you download the compiled Bootstrap and unzip the compressed folder then you see the following file structure and contents.

Bootstrap CSS files
    bootstrap/
  |—— css/
  | |—— bootstrap.css
  | |—— bootstrap.min.css
  | |—— bootstrap-theme.css
  | |—— bootstrap-theme.min.css

Bootstrap JavaScript files
  |—— js/
  | |—— bootstrap.js
  | |—— bootstrap.min.js

Bootstrap Fonts files
   |—— fonts/
  | |—— glyphicons-halflings-regular.eot
  | |—— glyphicons-halflings-regular.svg
  | |—— glyphicons-halflings-regular.ttf
  | |—— glyphicons-halflings-regular.woff