Internal legend viewer

Hello, I've got this idea because sometimes I need to know meaning of unknown signs and locating the legend externally is complicated.

As the simplest yet sufficient solution I suggest to use as legend a JPEG or PNG image located in same folder and named same as currently displayed map. Because Locus already can display images internally there is no need to use external app but show the legend on top of current map instead, ideally on tapping on a toolbar button or alternately add a map context menu item to maps browser.

As the more advanced solution link to any known map an external image located anywhere on card (more maps thus could share the same legend, especially favourable for more maps from same provider)