function of "including all his students"

[hela]

Dear teachers,
Would you please tell me what's the function of the following phrase and what is it called?

The teacher, including all his students, has decided not to enter the classroom.
the teacher = subject
has decided = verb
not to enter the classroom = direct object

What about "including all his students" ?

Thank you in advance

 

[5jj]

You asked a very similar question here. Please don't clutter up the forum with similar questions.