While the free map editor for the sci-fi shooter will have a content browser at launch, 343 Industries' Halo franchise development director Frank O'Connor made a quick comment over the weekend on the NeoGAF forums that mentions a custom game browser for the first time. He stated:
Once the custom game browser is available I think the community might get crazy legit.
PC Gamer got an official comment from a 343 Industries spokesperson confirming O'Connor's statement:
"Yes, a join-in-progress custom games browser is currently in development for Halo 5: Forge (Win10) and Halo 5: Guardians (Xbox One) and is planned for release in a future content update."
There's no word on how long we will have to wait before the custom games browser is added to Halo 5: Forge, but once it is implemented, it will turn the PC map editor into a full fledged free multiplayer shooter.