With Halo: The Master Chief Collection moving to PC over the last year, a lot of players hoped for a custom server browser in-game to quickly find community-ran games. Soon, we'll be getting exactly that, with testing set to begin in the next Master Chief Collection Flight version.
In this week's Master Chief Collection developer update, 343 Industries announced that it is currently preparing for the next MCC Flight, which is essentially an invite-only beta test for new features. One of the biggest new features is indeed a custom game browser, so players can host custom games open to all.
Currently, multiplayer in the Master Chief Collection works via matchmaking, with custom games requiring an invite and often being played amongst closed groups of friends.
With a server browser in place, Halo can have Counter-Strike esque community-ran games, with servers running a 24/7 map, or custom maps/modes etc. With a server browser in place, it also opens things up for community games with mods enabled.