Honestly surprised it took this long for someone to make this.
This is the classic Marathon 1 HUD, but modified to take the edge off just a little bit by extending it to fill modern 16:9 displays. For best results use 'Largest' HUD size in options.
With the extra space, an additional inventory page is displayed. In solo games, the extra page shows Ammunition at all times. In netgames, the extra page shows the Scoreboard at all times.
Based on the Classic M1 HUD plugin posted here by Hopper.
Wide Marathon 2 & Marathon Infinity HUD here.