Since google considered the handling of External Protocols by external applications
hazardous and it is no longer showing the checkbox with
"Always open these types of links in the associated app"
This can only be enabled using a policy change.
In linux this is performed by adding a file.
Windows uses a registry entry and is not addressed here.
As root create a directory /etc/opt/chrome/policies/managed
mkdir -p /etc/opt/chrome/policies/managed
Create an arbitrary named file using the default system editor.
In ths case the file is named external-protocol-checkbox.json.
editor /etc/opt/chrome/policies/managed/external-protocol-checkbox.json
Copy this Json content to the empty file.
Chrome version lower than 85.
{
"ExternalProtocolDialogShowAlwaysOpenCheckbox": true
}
Chrome version 85 or higher.
This allows all domains/origins from executing a magnet protocol link.
{
"AutoLaunchProtocolsFromOrigins": [
{
"allowed_origins": ["*"],
"protocol": "magnet"
}
]
}
Restart Chrome after the file has been added and open the policy using the local URL chrome://policy/.
Now the added entry should be visible.