I'm confused about the licensing of SRB2

[Conic]

I've heard that apparently it's GPLv2, but it doesn't actually include a copy of the GPL?

Can someone clear this up for me?

 

[SSNTails]

I don't think it needs to include a license.txt, since it says this right at the top of every source code file:

// This program is free software; you can redistribute it and/or
// modify it under the terms of the GNU General Public License
// as published by the Free Software Foundation; either version 2
// of the License, or (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.