Here it is necessary to declare information such as what is the title of the map, who is the author of the map, which data did the author use, where did the data come from (data sources), when was the application map, what is the purpose of the map, etc.
You also might want to add some text instructions on how to use this map. Indicate the users that the map is interactive!
The decision which items have to be included in the "about the map" part depends on the target audience. For example a map for children does not have to declare many items in the "about the project" part. Unlike a map that is made for scientists. In this case the "about the project" part of the application has to include detailed information about e.g. the origin and the up-to dateness of the data, etc.
These are just a few ideas of the items you might include, but feel free to expand!