How to delete categories via API

To delete Course Category via API, you need: 
1) Use GET method /odata/v2/CourseCategories to find all Categories with IDs:

2) After that, find the Category that you need to delete, and copy it's ID:

3) Finally, you could use DELETE method /odata/v2/CourseCategories({Id}) to delete the Category. There you should paste the copied ID to the special field. After that, press "Execute":

Now you deleted a Category.