the useage of the ampersat in javascript

I am learning javascript/unity and have just now come across @MenuItem and was wondering if the @ has a particular meaning in javascript or if its just something specific and internal to Unity itself? Just to clarify I understand @MenuItem and how to use it the question is just about the ampersat @ in general.

Thanks in advance for any help!

I believe @ is a char used for the editor interface itself. As @HideInInspector hides that variable in the editor inspector window. So yeah, I think it’s a Unity specific something. I don’t know for sure though.