Calling via credmaster, we get

(Note: I added a print(response.json()) at line 59 to get the json.)
{
"Username": "redacted@urmum.com",
"Display": "hidden@meme.com",
"IfExistsResult": 1,
"IsUnmanaged": false,
"ThrottleStatus": 0,
"Credentials": {
"PrefCredential": 1,
"HasPassword": true,
"RemoteNgcParams": null,
"FidoParams": null,
"SasParams": null,
"CertAuthParams": null,
"GoogleParams": null,
"FacebookParams": null,
"CaptchaParams": null
},
"EstsProperties": {
"UserTenantBranding": null,
"DomainType": 3
},
"IsSignupDisallowed": true,
"apiCanary": "asdfmovie4"
}
Going to log in manually, we see this

Note that here the value of IfExistsResult from /common/GetCredentialType is 5.
From the response:
{
"Username": "knavesec@example.com",
"Display": "obviously_redacted@example.com",
"IfExistsResult": 5,
"IsUnmanaged": false,
"ThrottleStatus": 0,
"Credentials": {
"PrefCredential": 1,
"HasPassword": true,
"RemoteNgcParams": null,
"FidoParams": null,
"SasParams": null,
"CertAuthParams": null,
"GoogleParams": null,
"FacebookParams": null,
"CaptchaParams": null
},
"EstsProperties": {
"UserTenantBranding": null,
"DomainType": 3
},
"FlowToken": "gowiththeflowman",
"IsSignupDisallowed": true,
"apiCanary": "some_garbage"
}
(Looks like this code is "Different IDP", not sure if that's used elsewhere, of just for passwordless auth.)
The only other difference I'm seeing is the FlowToken being set in the second.
Calling via credmaster, we get

(Note: I added a
print(response.json())at line 59 to get the json.){ "Username": "redacted@urmum.com", "Display": "hidden@meme.com", "IfExistsResult": 1, "IsUnmanaged": false, "ThrottleStatus": 0, "Credentials": { "PrefCredential": 1, "HasPassword": true, "RemoteNgcParams": null, "FidoParams": null, "SasParams": null, "CertAuthParams": null, "GoogleParams": null, "FacebookParams": null, "CaptchaParams": null }, "EstsProperties": { "UserTenantBranding": null, "DomainType": 3 }, "IsSignupDisallowed": true, "apiCanary": "asdfmovie4" }Going to log in manually, we see this

Note that here the value of
IfExistsResultfrom/common/GetCredentialTypeis5.From the response:
{ "Username": "knavesec@example.com", "Display": "obviously_redacted@example.com", "IfExistsResult": 5, "IsUnmanaged": false, "ThrottleStatus": 0, "Credentials": { "PrefCredential": 1, "HasPassword": true, "RemoteNgcParams": null, "FidoParams": null, "SasParams": null, "CertAuthParams": null, "GoogleParams": null, "FacebookParams": null, "CaptchaParams": null }, "EstsProperties": { "UserTenantBranding": null, "DomainType": 3 }, "FlowToken": "gowiththeflowman", "IsSignupDisallowed": true, "apiCanary": "some_garbage" }(Looks like this code is "Different IDP", not sure if that's used elsewhere, of just for passwordless auth.)
The only other difference I'm seeing is the
FlowTokenbeing set in the second.