When you choose ACME-DNS as the DNS provider in the LetsEncrypt SSL dialog what goes into the dns_acmedns_registration_file?

[vonHabsi]

When you select ACME-DNS after choosing a certificate based on DNS-01 challenge
the Credentials File Content * asks you to provide two parameters.

dns_acmedns_api_url = http://acmedns-server/
dns_acmedns_registration_file = /data/acme-registration.json

What should be the contents of /data/acme-registration.json in this case?

Do the settings vary from provider to provider, or is there a common minimum set all proivders must require?

In this case Dreamhost is the provider.

[matbad]

I found the pull request for the acme-dns plugin in #946, you can find an example there.

{
  "subdomain.your-domain.tld": {
    "username": "6e14735c-2c6a-447e-b63d-a23ac4438bd7",
    "password": "dd6gnYS-IxrQfDLbdPRX3hrFhS_SLrwbS0kSl_i8",
    "fulldomain": "3b750a0e-c627-423f-9966-4799c6a9533b.auth.acme-dns.io",
    "subdomain": "3b750a0e-c627-423f-9966-4799c6a9533b",
    "allowfrom": []
  }
}

subdomain.your-domain.tld is the domain, you want the certificate to be issued for.
The rest is the output, you get from acme-dns. You can find instructions for it on the Github page: https://github.com/joohoi/acme-dns
In my case I followed the installation process (not docker) and set up my own instance on a private virtual server, but you can simply use the public one: https://auth.acme-dns.io/

Keep in mind, that Nginx-Proxy-Manager is the client and does most of the magic. It requests, sets the TXT record and grabs the certificates.
acme-dns just gives you a subdomain, that Nginx-Proxy-Manager will update the TXT record for. But you have to point the CNAME for _acme-challenge.your-domain.tld to the subdomain you get when register at https://auth.acme-dns.io/register