What does .Net mean for a Unity developer?

Question

.NET

In vacancies they write that knowledge of .Net is required for a Unity developer. What is meant by this?
Never wrote windows applications with forms, worked only in unity. Perhaps I used .Net, but did not know what it was called? Enlighten, please.

Answer 1

Yes, in fact, everything that lies in the System namespace is .Net. Of course, not all of it will die, but the systems will also die. So if you've used List, Dictionary, Linq - then congratulations - you've used .Net.
And what is meant by vacancies honestly I will not say.

Answer 2

1 - .Net is not only for Unity. rather, it originally existed on its own. roam the history/architecture of Unity (what is Mono, IL2Cpp and many interesting things, not all of which are really necessary to start coding)

knowledge of .Net for Unity developer

could mean that

just knowledge of .Net

2 is not enough
- in various versions, Unity supported not only C #, there were Js, and even Boo. in this context

knowledge of .Net for Unity developer

could mean that

you need to be able to code in C # in Unity, and not in Js or Boo

3 - .. or both