Sets the name of the bridge to which a VM nic will be added to. This only applies to scenarios where ‘nic_mode’ is set to ‘tap’.
It can be set as a default to all nics:
bridge = virbr0
Or to a specific nic, by prefixing the parameter key with the nic name, that is for attaching ‘nic1’ to bridge ‘virbr1’:
bridge_nic1 = virbr1
No other documentation currently references this configuration key.