Thanks for your forum post. At the moment, there is really no way to accomplish what you describe. (i.e. a map tile/document representing a master map legend) In some cases, users have included a link in their map (bundle) description which directs users to a online document containing the map legend. Alternatively, when you create each of your maps you include a legend on them. If you would like to discuss further or provide more feedback please access the link which follows.