Are Amx Mod X plugins under GPL v3 license?

Question

The Amx Mod X is:

AMX Mod X is a versatile Half-Life metamod plugin which is targetted toward server administration. It has a wide array of scripting capabilities so people can write "plugins", or files which add on to a mod's functionality.

Plugins can take form in administrative services (adding new admin commands), statistics generation (StatsX), fun additions (godmode, etc), gameplay changes (WC3, CSDM), and much, much more! You can also write modules to expand the functionality of AMX Mod X and add to the scripting language.

...

Its license can be found on:

1. https://github.com/alliedmodders/amxmodx/blob/master/public/licenses/LICENSE.txt

AMX Mod X is licensed under the GNU General Public License, version 3, or (at your option) any later version.

As a special exception, the AMX Mod X Development Team gives permission to link the code of this program with the Half-Life Game Engine ("HL Engine") and Modified Game Libraries ("MODs") developed via the Half-Life 1 SDK as full replacements for Valve games. You must obey the GNU General Public License in all respects for all other code used other than the HL Engine and MODs. This extension, at your option, may also be granted to works based on AMX Mod X.

...

I tried to find some information about licensing it on the internet, but I could not find anything arruring:

1. License plugin on web address
2. Licensed Plugins
3. SourcePawn samples and GPL
4. Official AMXX Plugins on a Repository + License?

So, an AMXX (Amx Mod X) plugin follows the C syntax as follows:

#include <amxmodx>

#define PLUGIN  "New Plug-In"
#define VERSION "1.0.0"
#define AUTHOR  "Author"

public plugin_init()
{
    register_plugin(PLUGIN, VERSION, AUTHOR)
}

This file does not include a license clause, so:

1. By the Berne Convention the All rights reserved copyright granted by law to the plugin owner?
2. Or this plugin is under the open source GPL v3 as it is an derivative work from the AMXX API?

If I create & publish derivative works from it, i.e., add new functions as:

/**
 * Extended the plugin - 12-07-2017
 */
#include <amxmodx>

#define PLUGIN  "New Plug-In"
#define VERSION "1.1.0"
#define AUTHOR  "Author"

public plugin_init()
{
    register_plugin(PLUGIN, VERSION, AUTHOR)
    server_print( "Registered" )
}

The plugin owner can prosecute me by violating the All rights reserved copyright granted by Berne Convention law and take all my money?

Answer 1

I am not a lawyer, but here is my two cents.

Although the GPLv3 strongly recommends that you include a comment header declaring the license and the copyright information in each individual file, I don't believe it's required. https://www.gnu.org/licenses/gpl-howto.en.html

Unless stated otherwise in individual files, I would say the project as a whole is likely licensed under the GPLv3. The license file you reference states this in the last paragraph:

Some components of AMX Mod X use a license other than the GNU General Public License. You must also adhere to these additional licenses in all respects. See ACKNOWLEDGEMENTS.txt for further details.

If there is any uncertainty about a specific file, it is usually easiest to contact the copyright owner (or owner of the GitHub repository) directly, asking for clarification on its license. However, the owner of the GitHub repository may not be the copyright owner for a particular file, and hence, they may not know all of the appropriate licensing information. You, personally, are solely responsible for complying with licensing and copyright laws, regardless of if your source is in compliance.

You also ask about the Berne Convention in regards to regular copyright laws, which seems to be a duplicate from your earlier question: Is it possible to get rich prosecuting GitHub users from a non-lincesed fork?. I'll refrain from any conversation around that topic since you've already dedicated a thread to that.