For Roll20 the files you need are .css, .html, preview.png, and sheet.json. All the others are optional. They are intended to be used by front-end developers with NPM and compiled languages.
This is a template uses NPM to develop character sheets.
Dependencies are outlined in the package.json. Just use npm install to download them.
Start the compiles for SCSS & PUG with npm start.
If you wish to rename pug.pug and scss.scss be sure to update the package.json names.
QUnit is setup to do unit tests. Tests folder can be removed if you're not wriing tests.