What a course route shows before the learner's state has reached the
browser: the course title over placeholders, and nothing that depends on
whether the learner is enrolled.
The frame matches the course page's hero, so the page does not jump when the
real content replaces it. It carries no Enroll, no Start course and
no progress, because none of them can be known yet.
Example
if (!isSeeded) return<PendingCoursePagetitle={course.title}/>;
What a course route shows before the learner's state has reached the browser: the course title over placeholders, and nothing that depends on whether the learner is enrolled.