Minecraft wiki entry for Brigadier, associated text: Define command nodes with argument or literal branches
All the commands available in Java Edition are actually the literal branches available for the root command nodes instead of the actual executed commands.[5]
Modify/fork command source in command contexts
/execute as <target selector> may modify the command source to be multiple when multiple entities are selected
Active inspection on command parsing[6]
Listing all possible commands from current command node[7]
Handle command result real-time on execution success/failure
/execute store can store the command result to block/entity NBT data or scoreboard
Recursive command node redirection
/execute run redirects to the root node of the vanilla command dispatcher