How to configure Squid to allow access to cache manager when Squid port is not 3128

Issue

• When having squid listen on a different port than 3128 (port 80 in the example below) and restricting the Safe_ports ACL, the cache manager cannot be queried

  # grep "acl Safe_ports" /etc/squid/squid.conf
  acl Safe_ports port 80      # http
  # grep -w http_port /etc/squid/squid.conf
  http_port 80
  
  # squidclient -p 80 mgr:info
  HTTP/1.1 403 Forbidden
  Server: squid/3.5.20
  Mime-Version: 1.0
  [...]