The header on the view.php page of the mod_coursecertificate should correctly work on all supported Moodle versions:

• on 3.10 it should display the activity name as a header by calling $output->heading()
• on 3.11 it should display the activity name by calling $output->heading() and "Mark as done" button by calling $output->activity_information()
• on 4.0 it will display both activity name and "Mark as done" button as part of the $output->header(), so no additional calls are needed

There are no other php files that can be accessed from the browser in mod_coursecertificate so we don't need to modify them

Also I noticed that the page title is just acitvity name, it should be "coursename: activityname" like in all other activity types