manifest
Secure context: This feature is available only in secure contexts (HTTPS), in some or all supporting browsers.
Deprecated: This feature is no longer recommended. Though some browsers might still support it, it may have already been removed from the relevant web standards, may be in the process of being dropped, or may only be kept for compatibility purposes. Avoid using it, and update existing code if possible; see the compatibility table at the bottom of this page to guide your decision. Be aware that this feature may cease to work at any time.
The manifest attribute of the <html> element specifies a URL of an application cache manifest that is downloaded in the early stages of page load.
Note: manifest-based caching mechanism has been deprecated. Use service workers instead.
The manifest attribute only had an effect during early stages of page load, thus changing it via regular DOM interfaces had no effect. The deprecated Window.applicationCache interface was used instead. The attribute functionality has been superceded by the web app manifest, an external JSON file associated with the HTML file through a <link> with rel="manifest".
Browser compatibility
BCD tables only load in the browser