"Loading indicator" :).

That sounds as good as any. "Spinner" didn't seem right, and is too ambiguous. Thanks @TyDraniu!

Note that you can create a new Number pref on the <b>about:config</b> page to change the moving loading indicator to an hourglass. You can open the <b>about:config</b> page via the location/address bar. You can accept the warning and click "I accept the risk!" to continue. *https://support.mozilla.org/en-US/kb/about-config-editor-firefox ---- Firefox 63+ has support for "@media (prefers-reduced-motion)" and you can create a new Number pref named <b>ui.prefersReducedMotion</b> on the <b>about:config</b> page to enable or block some animations. In Firefox 78+ this includes the location bar breakout. In Firefox 80+ this replaces the tab loading indicator with an hourglass. * set the value to 1 if you want to block animations<br>ui.prefersReducedMotion = 1 * set its value to 0 if you want to see animations<br>ui.prefersReducedMotion = 0 *https://developer.mozilla.org/en/Web/CSS/@media/prefers-reduced-motion