.conventions.txt

Source: 
  https://dart.dev/tools/pub/package-layout  
  
Following is a summary of dart package convention -

my_dart_package/            - root package directory
  .packages                 - dependencies mapping with system cache
  pubspec.yaml              - meta-info and dependencies 
  pubspec.lock              - final used dependencies info
  bin/                      - executal main file
    main.dart
  doc/                      - documentations
  example/                  - application samples
  lib/                      - this app's library package
    string_merger.dart      - file to be imported by others
    src/                    - internal files used by this lib
      util.dart             - this file should not be exposed
  test/                     - unit test cases
    string_merger_test.dart
  web/                      - web specifc files
    index.html              - 
    style.css               - this can be in nested folders