Validators extending from CValidator all have a property named message. You can set this property in the corresponding validation rule to customize the error message. For example, the following validation rule uses an error message that is different from the default one:
So you want to use a fork of any existing vendor extension with your Yii 2 install and use the fork, instead of original source. This does not need you to push any update or register your package on packagist.org. You are recommended to follow the approach below:
How do you read and handle tabular data submission via form in Yii framework 2.0? Sometimes we want to collect user input in a batch mode. That is, the user can enter the information for multiple model instances and submit them all at once. We call this tabular input because the input fields are often presented in an HTML table.