Path to a file containing the accounts to use for external SIP bridging, organised by provider, in JSON format.
Here is a template of what should be in this file:
[{"name": "<user-friendly provider name for CLI output>",
  "pattern": "<regexp to match callee address>",
  "outboundProxy": "<sip:some.provider.example.com;transport=tls>",
  "registrationRequired": true,
  "maxCallsPerLine": 42,
  "accounts": [{
    "uri": "sip:account1@some.provider.example.com",
    "userid": "<optional (e.g. an API key)>",
    "password": "<password or API token>"
  }]
}]