Custom label and change in text hover for the button

gfroms-examples.php

function modify_gform_uninstall_button() {
	return '<input type="submit" name="uninstall" value="' . esc_attr__( 'Say Goodbye to Gravity Forms', 'gravityforms' ) . '" class="button" onclick="return confirm(\'' . esc_js( __( "Hi Client, just a quick Warning. ALL Gravity Forms data, including form entries will be deleted. This cannot be undone. 'OK' to delete, 'Cancel' to stop. If you'd like to keep anything, please export your form data", 'gravityforms' ) ) . '\');"/>';

}
add_filter('gform_uninstall_button', 'modify_gform_uninstall_button');