Find it on the console under Settings → General → Network settings → Advanced settings. Giving the Xbox a DHCP reservation on the XB7 keeps the address stable. The choice is applied immediately and kept in memory for this run; add "targets": {"xbox_ip": "…"} to config.json (or start with --xbox IP) to make it permanent.

Plex mode watches the Plex server (on its port 32400, which works even when Windows' firewall drops pings) and each player, and with a token reads what the server is doing: Direct Play or Transcode and its speed, CPU, background tasks and buffering. To find the token: open Plex in a browser, open any movie or episode, choose ⋯ → Get Info → View XML; the address of the page that opens ends in X-Plex-Token=…. Paste the part after the = here. It is saved in config.json on this computer only (mode 600), sent only to your Plex server, and never shown, logged or exported. Players in a session are added automatically.