Looks like this in N8N for single use:

To reuse it in all nodes, this should work:
https://community.n8n.io/t/how-to-authorize-using-bearer-token/25674

And we are having trouble figuring out how to tell the destination cloudron to pull a backup from a remote location.

{
  "meta": {
    "instanceId": "8d8e1b7ceae09105ea1231dc6c31045b9d36dc713f8e22970f6eacf9f1f4d996"
  },
  "nodes": [
    {
      "parameters": {},
      "id": "4be687c9-4a4b-4be3-a8fc-d1405a66fa95",
      "name": "When clicking \"Execute Workflow\"",
      "type": "n8n-nodes-base.manualTrigger",
      "typeVersion": 1,
      "position": [
        680,
        320
      ]
    },
    {
      "parameters": {
        "url": "https://my.demo.cloudron.io/api/v1/apps",
        "authentication": "genericCredentialType",
        "genericAuthType": "httpQueryAuth",
        "options": {}
      },
      "id": "33c66a41-753b-491a-bf03-8683f86b95c5",
      "name": "PullAppsFromSource",
      "type": "n8n-nodes-base.httpRequest",
      "typeVersion": 4.1,
      "position": [
        900,
        320
      ],
      "credentials": {
        "httpHeaderAuth": {
          "id": "11",
          "name": "RobCloudron-Demo"
        },
        "httpQueryAuth": {
          "id": "12",
          "name": "Query Auth account"
        }
      }
    },
    {
      "parameters": {
        "jsCode": "// Loop over input items and add a new field called 'myNewField' to the JSON of each one\nfor (const item of $input.all()) {\n  item.json.myNewField = 1;\n}\n\nreturn $input.all();"
      },
      "id": "a1d203d0-4d01-421a-9d88-7299f8f515ce",
      "name": "ManipulateResponse",
      "type": "n8n-nodes-base.code",
      "typeVersion": 1,
      "position": [
        1120,
        320
      ]
    },
    {
      "parameters": {
        "url": "=https://my.demo.cloudron.io/api/v1/apps/{{ $json.apps[0].id }}/backups",
        "authentication": "genericCredentialType",
        "genericAuthType": "httpQueryAuth",
        "options": {}
      },
      "id": "9c925efa-458f-4599-8172-7d9fafc3ce23",
      "name": "PullBackupsFromSource",
      "type": "n8n-nodes-base.httpRequest",
      "typeVersion": 4.1,
      "position": [
        1320,
        320
      ],
      "credentials": {
        "httpHeaderAuth": {
          "id": "11",
          "name": "RobCloudron-Demo"
        },
        "httpQueryAuth": {
          "id": "12",
          "name": "Query Auth account"
        }
      }
    }
  ],
  "connections": {
    "When clicking \"Execute Workflow\"": {
      "main": [
        [
          {
            "node": "PullAppsFromSource",
            "type": "main",
            "index": 0
          }
        ]
      ]
    },
    "PullAppsFromSource": {
      "main": [
        [
          {
            "node": "ManipulateResponse",
            "type": "main",
            "index": 0
          }
        ]
      ]
    },
    "ManipulateResponse": {
      "main": [
        [
          {
            "node": "PullBackupsFromSource",
            "type": "main",
            "index": 0
          }
        ]
      ]
    }
  }
}

Remote Cloudron B
GET
https://my.example.com/api/v1/apps
https://my.example.com/api/v1/apps/{appid}
use appStoreId, subdomain, domain
https://my.example.com/api/v1/apps/{appid}/backups
pick latest
https://my.example.com/api/v1/backups
https://my.example.com/api/v1/settings/backup_config
merge backup config with app backup config??

Local Cloudron A
POST
https://my.example.com/api/v1/apps/install
use appStoreId, subdomain, domain; get id
??? import merged remote backup config
https://my.example.com/api/v1/apps/{appid}/restore
use payload from remote app backup config???

What would the import calls looks like? @girish

The Restore path doesn't seem to be the right thing to use as it expects a local backup id.

How does the UI do the import via the API?

This brings to mind another idea that Cloudron could have a 3rd party API plugin feature integration that would allow for such customizations just as Wordpress plugins do.

For me this does clarify the idea that a tool/script should be run from the destination Cloudron A to pull an app from the App backups of Cloudron B.

This would also allow for devs to share their pre-packaged Apps for testing and more (using group/domain visibility), similar to the Github fork feature, by sharing the backup configuration.

The next bit would be to iterate that import process for a list of App IDs provided.

If this were to be polished later as a plugin/feature, remote clone of an app across Cloudrons would be a few clicks away.

Another external option would be to use N8N to automate the process in a more visual workflow.

Are you aware of anyone writing such a script?

maybe you could restore the whole cloudron with dry-run option and then cut over DNS one-by-one? https://docs.cloudron.io/backups/#dry-run

But how could one restore onto a VPS with an already existing Cloudron with lots of other apps already there?

Otherwise, I guess writing a small script against the Cloudron API will come in handy.