Pandoc bills itself as "a universal document converter." It can read input files in nearly twenty markup formats (including Markdown, reStructuredText, textile, and HTML) and convert them to over forty other formats (including docx, odt, epub, tei, and many, many more). A diagram of the built-in conversions is shown on the bottom of Pandoc's "about" page. These format conversions can be used to bring content to new devices. For example, a user could download the HTML of a web page and convert it to an ebook for offline reading. Pandoc can also be used for document production. For example, users can write presentation slides in Markdown using their favorite text editor, then use Pandoc to generate a PowerPoint presentation. The same Markdown file can also be used to generate a reveal.js version of the presentation that can be uploaded to a website. Pandoc understands the Citation Style Language (CSL) of citationstyles.org and can also generate bibliographies for academic work. Pandoc is a free software, released under the GNU General Public License with source code available on the "installing" page. The "installing" page also lists installers for Windows, macOS, Linux, and BSD operating systems.