How to connect to WH-1000XM3 Headphones from Ubuntu 20.04

The Bluetooth connection to WH-100XM3 headphones from Ubuntu 20.04 can be a bit hit and miss. This seems especially so if you use the headphones on more than one machine. Here is a command line session record of me using bluetoothctl (the commands I entered are shown in underlined bold):

$ bluetoothctl
Agent registered
[bluetooth]# scan on
Discovery started
[CHG] Controller E0:D4:64:02:D3:88 Discovering: yes
[NEW] Device 94:DB:56:18:25:5D LE_WH-1000XM3
[CHG] Device D8:FC:93:42:60:A7 RSSI: -35
[CHG] Device D8:FC:93:42:60:A7 TxPower: 10
[bluetooth]# devices
Device 8C:EA:48:5B:E5:D3 [TV] Samsung AU7100 43 TV
Device D8:FC:93:42:60:A7 IVYSAUR
Device 94:DB:56:18:25:5D LE_WH-1000XM3
[bluetooth]# connect 94:DB:56:18:25:5D
Attempting to connect to 94:DB:56:18:25:5D
[CHG] Device 94:DB:56:18:25:5D Connected: yes
[CHG] Device 94:DB:56:18:25:5D Name: WH-1000XM3
[CHG] Device 94:DB:56:18:25:5D Alias: WH-1000XM3
[CHG] Device 94:DB:56:18:25:5D Modalias: usb:v054Cp0CD3d0422
[CHG] Device 94:DB:56:18:25:5D UUIDs: 00000000-deca-fade-deca-deafdecacaff
[CHG] Device 94:DB:56:18:25:5D UUIDs: 00001108-0000-1000-8000-00805f9b34fb
[CHG] Device 94:DB:56:18:25:5D UUIDs: 0000110b-0000-1000-8000-00805f9b34fb
[CHG] Device 94:DB:56:18:25:5D UUIDs: 0000110c-0000-1000-8000-00805f9b34fb
[CHG] Device 94:DB:56:18:25:5D UUIDs: 0000110e-0000-1000-8000-00805f9b34fb
[CHG] Device 94:DB:56:18:25:5D UUIDs: 0000111e-0000-1000-8000-00805f9b34fb
[CHG] Device 94:DB:56:18:25:5D UUIDs: 00001200-0000-1000-8000-00805f9b34fb
[CHG] Device 94:DB:56:18:25:5D UUIDs: 7b265b0e-2232-4d45-bef4-bb8ae62f813d
[CHG] Device 94:DB:56:18:25:5D UUIDs: 81c2e72a-0591-443e-a1ff-05f988593351
[CHG] Device 94:DB:56:18:25:5D UUIDs: 931c7e8a-540f-4686-b798-e8df0a2ad9f7
[CHG] Device 94:DB:56:18:25:5D UUIDs: 96cc203e-5068-46ad-b32d-e316f5e069ba
[CHG] Device 94:DB:56:18:25:5D UUIDs: b9b213ce-eeab-49e4-8fd9-aa478ed1b26b
[CHG] Device 94:DB:56:18:25:5D UUIDs: f8d1fbe4-7966-4334-8024-ff96c9330e15
[CHG] Device 94:DB:56:18:25:5D ServicesResolved: yes
[CHG] Device 94:DB:56:18:25:5D Paired: yes
Connection successful
[CHG] Device 94:DB:56:18:25:5D RSSI: -54
[CHG] Device 94:DB:56:18:25:5D Name: LE_WH-1000XM3
[CHG] Device 94:DB:56:18:25:5D Alias: LE_WH-1000XM3
[WH-1000XM3]# exit
$

If the connection fails then you might need to remove the LE_WH-1000XM3 entry from the device list by entering remove followed by its MAC addess, for example: [bluetooth]# remove 94:DB:56:18:25:5D, and then rerun the scan and connect commands.