Modify config.ini.php to limit available bridges. Those changes should be applied in the [system] section.
Enable all bridges
[system]
enabled_bridges[] = *
Enable some bridges
[system]
enabled_bridges[] = TwitchBridge
enabled_bridges[] = GettrBridge
Enable all bridges (legacy shortcut)
echo '*' > whitelist.txt
Enable some bridges (legacy shortcut)
echo -e "TwitchBridge\nTwitterBridge" > whitelist.txt