REST API - Basic authentication UI stored in HEADER

Hello,

Little bit of a weird but a small question.

In my function Web.Contents I make a call to an URL which is a simple login page. If you go to the login page when opening the URL it works without error and shows a simple status code like 200. If in Power BI I use anonymous as authentication it works, but it also works when I use basic authentication with a username and password. When I use anonymous my RelativePath won't work because it requires basic authentication to call the API.

• I know that Power BI service does some static analysis in which it first evaluates my root URL with the credentials I use, so here "https://BLUH.ionbiz.com" with the basic authentication (which is actually not needed). If it works then it will execute the rest of the parameters in Web.Contents so my RelativePath and Query. My question is now, does it store the basic authentication credentials afterwards in my header to call my RelativePath where basic authentication is actually needed?

let
    HTTPHeader = [RelativePath = "api/Plannings/GetList", Query = [page="0", pageSize="0", departmentShortName="", departmentExternalCode="", resourceId="", dateFrom="", dateTo="", projectId="", taskId="", lastModifiedDate=""], Headers = [#"Content-Type"="application/json"]],
    GetPlannings = Json.Document(Web.Contents("https://BLUH.ionbiz.com", HTTPHeader))
in
    GetPlannings 

Kind regards