The Geyser plugin can be used in numerous different configurations to provide a very useful and much needed bridge between Minecraft Java Edition™ and Minecraft Bedrock Edition™. A highly adaptable project, Geyser can run as either a standalone piece of server software, or as a plugin depending upon the existing individual hosting arrangements of each particular Minecraft server.
At UniversalCraft we have chosen to deploy Geyser as a Waterfall/Bungeecord plugin on our public-facing proxy servers. It is this plugin that listens on UDP port 19132 for incoming connections from Minecraft Bedrock Edition™ clients and handles all packet translations to allow those clients to function correctly when connected to a Minecraft Java Edition™ server.
This plugin does not provide any additional in-game commands of its own.