1.4.5 sass.variables.misc Miscellaneous variables
$indent-amount controls the amount lists, blockquotes and comments are indented.
$include-rtl controls whether RTL styles are output. Rather than include a separate *-rtl.css file, Zen 6 uses Drupal 8's standard [dir="rtl"] selector for RTL language support.
Source:
init/_variables.scss, line 203