I think the WKWebView was optional, which is the iOS webview (In the 6.10 release notes). I remember one of the reasons they introduced the crosswalkplugin was to fix issues with older versions of Android. They do not recommend turning it off.
Recently Mendix published a blog on hybrid mobile, in which they have a list of needed plugins. That is currently the only place I know which displays which plugins are needed. They probaly should add it to the documentation.