assets/web-template/css/pp-article.css is the commented css file intended to
be uploaded to OJS. It contains css for styling the html-fulltext as well as
css rules to style the OJS website. Because of compatibility reasons (OJS fails
to recognize this file as a css file and upload fails), the file:
assets/web-template/css/pp-article-no-comments.css is used. It has the same
css rules as the first file, but all comments are stripped. (OJS doesn't complain then).