MDL-38106 introduced the intro field into the lesson module however it is only displayed on the course page if the corresponding checkbox is set. This is inconsistent with the other modules in moodle core. Other modules display the intro to students when the activity is viewed (either at the top of the page like in assignment or glossary or on a separate introduction page like in quiz).

This issue proposes to add a separate introduction page to lesson that should display the intro text if set (Similar to that of the quiz module)