Hi, what the syntax is in Action Mailer Basics rails guide ?

class UserMailer < ActionMailer::Base
   def welcome_email(user)
      recipients    user.email
      from          "My Awesome Site Notifications <[email protected]>"
      subject       "Welcome to My Awesome Site"
      sent_on       Time.now
      body          {:user => user, :url => "http://example.com/login"}
   end
end

How should i understand the construction, like

from "Some text for this field"

Is it an assignment the value to a variable, called "from" ?