Pug, formerly known as Jade is a html templating language. Prepros comes with Pug support out of the box. Prepros can recognize and compile both .pug and .jade files.
You can click the path to manually change the output path or use Output Settings to adjust output path for all less files.
Enable this option to compile a file every time you save it in a code editor.
Enable this option to output expanded html.
If you are importing a pug file from another file, the importing file is compiled whenever a imported file is saved in code editor.
extends ./b.pug import ./c.pug //This file is compiled whenever b.pug or c.pug is changed
Learn more about Pug from Pug website