What do these ASP.Net user controls (.ascx) in a Tridion Page do?

I got this code from an SDL Tridion site related to render ASP.Net user controls on the page.

What I understand is the body tag menu, content, search results are .ascx file. But I don't understand the other controls they have used. Can anyone please explain this code snippet?

<%@ Page Language="C#" %>
<html>
  <head>
    <title>
      <tridion:content ExpectXmlContent="true" XPath="//tcm:Content/tridion:Content/tridion:title" runat="server"/>
    </title>
    <tridion:content templateuri="tcm:47-3016-32" runat="server"/>
    <tridion:track runat="server" xpath="//tcm:Metadata/tridion:Metadata/tridion:category" pageuri="tcm:47-2966-64" />
    <tridion:secure issecured="false" redirecturl="~/login/login.aspx" runat='server'/>
  </head>
  <body>
    <tridion:menu menutype="topnav" runat="server"/>
    <tridion:content templateuri="tcm:47-3052-32" runat="server"/>
    <tridion:searchresults Category="Categories" templateuri="tcm:47-3058-32" runat="server"/>
  </body>
</html>

Solution

Check the projects web.config file, there should be a <controls> tag where there'll be a reference to an assembly that's using the "tridion" tag prefix.

You can then use something like ILSpy to decompile the assembly and get a clearer idea of what's going on.