In this book, you will find several text styles that distinguish between different kinds of information. Here are some examples of these styles and an explanation of their meaning.

Code words in text, database table names, folder names, filenames, file extensions, pathnames, dummy URLs, user input, and terminal commands as follows: "So if we changed the route URL to mastering_drupal_8/test/{message}, we would change the controller function to:"

A block of code is set as follows:

name: Test
type: theme
description: A test theme.
core: 8.x
libraries:
 - test/global
regions:
 header: Header
 content: Content # the content region is required
 sidebar_first: 'Sidebar first'
 footer: Footer 

Any command-line input or output is written as follows:

# composer create-project drupal/drupal

New terms and important words are shown in bold. Words that you see on the screen, for example, in menus or dialog boxes, appear in the text like this: "Clicking the Next button moves you to the next screen."