You can think of it as the number of warzone missions you've completed. On PC, hovering over the mission would tell you the number, though I'm not sure if there's an equivalent on console. However, since there's 10 warzone missions per stage, you can also just count the stages, then add the remainder from your current stage. That said, if the Tier V objective hasn't changed since Season 1 on PC, there's an objective to complete all 110 warzones, which means you basically can just keep going until you run out of missions to run (assuming you're aiming to complete all season tiers).

Hopefully this translates well or you can read it well enough as-is. My German is worse than Google's. :(