Block category: Common
The Common category includes the following blocks: Paragraph, image, headings, list, gallery, quote, audio, cover, video. The paragraph block is the default block type. It should not have any alignment…
Post Format: Video (WordPress.tv)
https://wordpress.tv/2009/03/16/anatomy-of-a-wordpress-theme-exploring-the-files-behind-your-theme/ Posted as per the instructions in the Codex.