View the original community article here
Last tested: Jul 1, 2019
Chromium is an open source version of Chrome, and it is what Looker uses to render PNGs/PDFs. Chromium can be run in headless mode, meaning it will start up on the Looker server without having a user interface to interact with and can be controlled remotely. Each time a render job is run, Chromium is started in headless mode and used to try to take a screenshot of the Looker content.