Used with WebSettings.MixedContentMode In this mode, the WebView will attempt to be compatible with the approach of a modern web browser with regard to mixed content. Some insecure content may be allowed to be loaded by a secure origin and other types of content will be blocked. The types of content are allowed or blocked may change release to release and are not explicitly defined. This mode is intended to be used by apps that are not in control of the content that they render but desire to operate in a reasonably secure environment. For highest security, apps are recommended to use WebSettings.MixedContentNeverAllow.

[Android Documentation]