Link field, what its origin

Hello;

From where link field is taken originally? What its name originally?

Any development happened on it to work as it is working in ERPNext?

Regards
Bilal

Link field as it’s name suggests is used to Link your current form or doctype to another existing doctype. When you mention ‘Options’ in the field of type Link, you are prompting which doctype it must suggest entries from in it’s dropdown.
Here ( Fetch a Field Value from a Document into a Transaction ) is an scenario to help you with a Link field use case.
You can also go through the Frappe tutorial (Frappe Framework Tutorial) to get a good hands on experience with what purpose the basic features serve.

No I do not mean what does it do, I know it well.
I am asking, from where frappe got it?
As u know, frappe and erpnext is bootstrap based and html. So what originally this field?
Is it normal drop down fields with some format changes or what?

Again, I am asking what this field in javascript or in html?

Regards
Bilal

Actually this link field is text search auto complete field and I got to know it. But how it is formatting the results (in two lines and so on)?

Regards
Bilal