The map shows the vehicle's current position, home position, and direction (which may differ from where it is heading due to sideslip for example). It also shows the recent flight path in red, and the expected path if one is defined in blue(e.g. an orbit destination, or the mission path).
Expected flight path and planned flight path
Map Grid (MGRS)
You can enable an MGRS coordinates overlay by toggling the checkbox in Settings > General > Fly View > Display MGRS coordinates.