Why there is a ^ Cap symbol in `pubspec.yaml` file under dependencies

I not sure why there is a cap symbol in pubspec.yaml file under dependencies. See below image.

The project is working even without the cap symbol.

This is called caret syntax:

Caret syntax expresses the version constraint in a compact way. ^version means the range of all versions guaranteed to be backwards compatible with the given version. This range would include all versions up to the next one to introduce a breaking change. As Dart uses semantic versioning, this would be the next major version for any package version 1.0 or later or the next minor version for any package version earlier than 1.0.

So in your example, you've got:

• meta: ^1.1.6 - equivalent to >=1.1.6 <2.0
• equatable: ^0.2.3 - equivalent to >=0.2.3 <0.3.0
• cupertino_icons: ^0.1.2 - equivalent to >=0.1.2 <0.2.0