What is the name of the mail server operation mode when the attachment is stored only in 1 instance?

Question

Mail server

Good afternoon. Actually a subject. What is the name of the mail server operation mode when the attachment is stored only in 1 instance? Roughly speaking, 1 employee sent a letter with a 10MB attachment to his 100 colleagues. So that the attachment is not copied aimlessly 100 times, but a symbolic link to it is created ... It just flew out of my head, and no one nearby can tell :)

Answer 1

Deduplication ?