Microsoft today sent out update 2305.230410-2200 for members of the Alpha channel’s Xbox Insider program. The most notable improvement in this update is the change of Discord to use player code names.

After Xbox players install this update, the name displayed on Discord will no longer be the Discord account, but the Xbox gamer codename, which helps players more easily identify their friends.
The Alpha update also fixes the handle bug, adds new language options, and optimizes Xbox Game Pass Quests, more details can be found here.
The following official description of the player codenames from Microsoft:
A gamer codename is your alter ego in the Xbox world. It consists of an alias, an optional avatar or picture (called a gamer picture), and some other information to represent yourself when you play and share games with others in the Xbox community.