CSS MAP file is only used to map CSS to SCSS file format, in a sense while debugging your code from dev-tools you can look at the CSS in a more organised manner instead of clutter.
Therefore map file has no actual use for your code, so you can safely delete the file. To remove the linking of the map file from the CSS or JS file, just delete the last comment of the respective file.
If you are using the bootstrap CDN link it is hight recommended to download and use it offline. It even increases your website performance.
