A meta-tag protocol from Twitter (now X) for controlling the rich preview shown when a link is posted on the platform. Tags use the
twitter: namespace, e.g. <meta name="twitter:card" content="summary_large_image">. Common card types include summary, summary_large_image, and player. If Twitter Cards are absent, X falls back to Open Graph tags — so most sites set the Open Graph tags first and only override specific Twitter-Card values where the rendering differs.