There are better places I’m sure, but a quick Google for it turned up this and this.  Now most places are saying it shows only your ammo, THIS IS NOT TRUE.  I remember seeing more than that when I was using it back in the day, and I finally found where the extra stuff is.  From the release notes:

When installed, this patch will add a UT2004 LCD display screen.  This display screen has 3 modes that can be toggled via console commands.  They are:

Mode 0    - display real-time network stats
Mode 1    - display a scoring summary
Mode 2     - display weapon ammo counts

You can change LCD modes using the “LCDMode” console command.  The format is:

“lcdmode <x>” where x is the mode to display.  Additionally, you can use the NextLCDMode and PrevLCDMode commands to move between them.