One is to configure the whole domain, with a mimemappings.properties file.
This is the entry in config.xml (you can do it in console, domain, webapplications):
<web-app-container> <x-powered-by-header-level>NONE</x-powered-by-header-level> <mime-mapping-file>./config/mimemappings.properties</mime-mapping-file> </web-app-container>
Mime Mapping File Returns the name of the file containing mime-mappings for the domain. Format of the file should be: extension=mime-type Example: htm=text/html gif=image/gif jpg=image/jpeg If this file does not exist, WebLogic Server uses an implicit mime-mapping set of mappings defined in weblogic.utils.http.HttpConstants (DEFAULT_MIME_MAPPINGS). To remove a mapping defined in implicit map just set it to blank. MBean Attribute: WebAppContainerMBean.MimeMappingFile
The other way is to create a mime-mapping entry in your web application's web.xml
For a general presentation of IE11 and Mime: https://msdn.microsoft.com/en-us/library/ms775148%28v=vs.85%29.aspx
Remember also the default-mime-type attribute in weblogic.xml. "This element allows the user to specify the default mime type for a content-type for which the extension is not mapped."