Find out who is the admin(s) for a git repo

If you have push access to this repository, you can use Github API to find collaborators

You will need an access token, the endpoint https://api.github.com/repos/ORG/REPO/collaborators gives you a list of all collaborators with the list of permission type for each of them :

"permissions": {
    "admin": true,
    "push": true,
    "pull": true
  }

You can use curl and jq (to parse JSON response) like this :

curl https://api.github.com/repos/ORG/REPO/collaborators \
     -H "Authorization: Token ACCESS_TOKEN" | \
     jq '[ .[] | select(.permissions.admin == true) | .login ]'

You can also use the v4 (GraphQL) API for this:

query { 
  repository (owner:"ORG",name:"REPO") {
    collaborators (first:100) {
      totalCount
      edges {      
        permission
        node {
          login
          name  
        }
      }
      pageInfo {
        endCursor
        hasNextPage
      }
    }
  }
}

and look for results that have "permission": "ADMIN"