The map is divided into Maidenhead Locator Squares (unlabelled). “Large Square” locator letters are also displayed on the map (“IO”, “JO” etc).
When propagation is present and reported, frequencies in the squares indicate the MUF in those squares in MHz as calculated by the Live MUF application for contacts during the last 15 minutes.
White parallel lines crossing the map = day/night terminator
Yellow star = Sub-solar point
The data block in the bottom left corner includes the date and the start/end times for the 15 minute period of the current map in UTC.