INSTALL

1. In the composer.json file in require-dev
put "jlle/env-info": "^0.1.2"

It is important that you do not put yourself in

"requires": {

}

In autoload-dev from the composer.json file put

"autoload-dev": {
  "psr-4": {
      "App\\Tests\\": "tests/",
      "Jlle\\EnvInfo\\": "vendor/jlle/env-info/src/"
  }
},

2. At the root of the project and at the same level as composer.json

create an empty file with the name: envinfopass

This is so that even in a development environment, the information cannot be accessed if this file does not exist.
In production should not be created

3. In the config/routes.yaml file
Introduce:

envinfo:
  path: /envinfo
  methods: GET
  controller: Jlle\EnvInfo\Controller\EnvInfoController::envInfo
  
4. In the config/services.yaml file
Introduce:

Jlle\EnvInfo\:
        resource: '../vendor/jlle/env-info/src/' 
        
        
Example of services.yaml file:

parameters:

services:
    # default configuration for services in *this* file
    _defaults:
        autowire: true      # Automatically injects dependencies in your services.
        autoconfigure: true # Automatically registers your services as commands, event subscribers, etc.

    # makes classes in src/ available to be used as services
    # this creates a service per class whose id is the fully-qualified class name
    App\:
        resource: '../src/'
        exclude:
            - '../src/DependencyInjection/'
            - '../src/Entity/'
            - '../src/Kernel.php'
            
    Jlle\EnvInfo\:
        resource: '../vendor/jlle/env-info/src/'     
        
        
then you will have to launch composer install        

The url to see the variables depending on the configured environment is

http://localhost/envinfo

remember that if you have specified a port you should put it

http://localhost:8000/envinfo