What have you learned during your studies?
Your subject-specific competences are unique to your particular educational program. We can also call them "technical" skills that make you able to manage a certain job or specific tasks. They are what you have learned in the courses you have taken and the knowledge you have gained from them.
They are often the easiest competences to name, as you can go through your course list and see what you have learned. What topics and themes have you been through? Look through the course descriptions and write them down.