Weird page URLs that shouldn't exist

I was just checking Google Analytics and came across some URLs that shouldn't exist, but are indexable by search engines:

https://www.openaccess.cam.ac.uk/todo-what-todo-what-todo-i-dont-know

https://www.openaccess.cam.ac.uk/custom/researchprofessional.oaeproject.org/index.html

This one looks like it might be an A/B test experiment:
https://www.openaccess.cam.ac.uk/openaccessa