Spring Cloud Config Server

I looked at the code for a number of spring cloud config servers in github repo and below are the 2 values that are provided as part of property file. I believe in order to connect to https end point of github , user id and password are also necessary. Could these perhaps be part of environment variables?

server.port=7070
spring.cloud.config.server.git.uri=https://

EDIT:

Below is the example that I saw in spring website. However in all the github repos within my enterprise I don't see userid and password being set as they are sensitive info. How could it be set or config server access github url , if uid / pwd is not provided in the property file?

spring:
  cloud:
    config:
      server:
        git:
          uri: https://github.com/spring-cloud-samples/config-repo
          username: trolley
          password: strongpassword