<!--

Use this page to write about the node topic. On the right
you can see a live preview. This page uses the CommonMark
syntax (https://commonmark.org).

Articles ought to provide a thorough overview of specific
topics, and contain only objective and informative content.
Please keep in mind these guidelines when editing:

  - Use an expository writing style
  - Provide references (primary sources)
  - Use a simple language as much as possible
  - Be concise and clear, do not be vague or evasive
  - Summarize topics using your own words. Do not
    copy-paste from books or other resources

-->

