The extension is missing a TimedMediaHandler.namespaces.php; so its namespace display cannot be localized on local wikis, as opposed to some recent new extensions such as Gadgets, Scribunto, Flow, etc. Thanks.
(namespace translation was requested at T180052: Creation and update of namespaces in Mirandese Wikipedia (mwlwiki) but I cannot honor it given that this extension does not seem to support localized namespaces).