Merge pull request #15709 from edx/release-mergeback-to-master

common/djangoapps/course_modes/models.py

common/djangoapps/course_modes/tests/test_models.py

common/djangoapps/course_modes/views.py

lms/djangoapps/ccx/tests/test_field_override_performance.py

lms/djangoapps/courseware/tests/test_course_info.py

lms/djangoapps/courseware/tests/test_views.py

lms/djangoapps/courseware/views/index.py

lms/djangoapps/courseware/views/views.py

lms/djangoapps/discussion/views.py

lms/djangoapps/experiments/utils.py

lms/templates/main.html

lms/templates/user_metadata.html

...eatures/course_experience/tests/views/test_course_home.py

...ures/course_experience/tests/views/test_course_updates.py

openedx/features/course_experience/views/course_sock.py

scripts/xss_linter.py