If you want to find orders containing bundles in Shopify Flow and send an internal email, you can use the following steps.

1. Go to Shopify Flow page on your store.
2. Create a new flow.
3. Select Trigger: Shopify > Start when: Order Created.
4. Then + Add an action: Flow > For each item in order.lineItems.
5. Then + Add a condition: Check if Line item group title not empty and exists.
6. Then + Add an action: Send an internal email.

After these steps, Shopify Flow will send an email for each order that contains a bundle.
You can customize the email content and recipients as you wish.

The tricky part is the line item group title 😉

I found this path with following GraphQL query:

query GetOrder($id: ID!) {
  order(id: $id) {
    lineItems(first: 10) {
      edges {
        node {
          title
          lineItemGroup {
            title
          }
        }
      }
    }
  }
}

{
  "id": "gid://shopify/Order/1234567890"
}