i found a buncha source code files and i was wondering if i could edit these so mabye i could jump higher or run faster? This looks like the file that would let me do that.

/***
*
*  Copyright (c) 1999, Valve LLC. All rights reserved.
*
*  This product contains software technology licensed from Id
*  Software, Inc. ("Id Technology").  Id Technology (c) 1996 Id Software, Inc.
*  All Rights Reserved.
*
*   Use, distribution, and modification of this source code and/or resulting
*   object code is restricted to non-commercial enhancements to products from
*   Valve LLC.  All other use, distribution, or modification is prohibited
*   without written permission from Valve LLC.
*
****/
//
//  cdll_int.h
//
// 4-23-98
// JOHN:  client dll interface declarations
//
etc...