These are dynamically created custom configuration(s) that will always overwrite your server.toml. You should always adjust these depending on your environment.
dev.json
Development mode with VUE DEBUG running. Only allows 1 Player on a local machine to connect. Has Reconnect.
devtest.json
Developent mode with 32 Players and NO VUE DEBUG. Has Reconnect.
prod.json
Production mode with all core resources loaded. No Reconnect