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 of any kind. It should just flow like you would normally expect. Nothing fancy. Just straight up text, free flowing,…
This post tests various embed blocks: https://twitter.com/WordPress/status/1057136472321613824 Twitter, wide width https://youtu.be/ex8fMxXJDJw YouTube https://www.facebook.com/6427302910/posts/10156380423617911/ https://www.instagram.com/p/BpmueLLgEn_/?utm_source=ig_share_sheet&igshid=1hcxphic7p9e2 https://wordpress.tv/2018/10/14/kjell-reigstad-allan-cole-how-we-made-our-first-gutenberg-powered-theme/ WordPress TV, full width
https://twitter.com/nacin/status/319508408669708289 This post tests WordPress' Twitter Embeds feature.
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.