The bulk of the rules are dynamically defined, whose purpose is to add type declarations to properties and methods.
These are driven by generated signature files.
To generate a new signature file, run the following commands;
php scripts/signature-builder.php ../craft4/craftcms/cms craft-cms-40 -n craft -e craft\\test -a lib/yii2/Yii.php,src/Craft.phpphp scripts/signature-diff.php ../craft3/craftcms/cms craft-cms-40 -a lib/yii2/Yii.php,src/Craft.phpphp scripts/signature-cleanup.php craft-cms-40(Replace ../craft4/craftcms/cms with the path to the source folder at the target version, and
craft-cms-40.php with the signature file name.)
The source folder must have Composer dependencies installed, and its Composer-generated autoloader must be optimized:
> composer dump-autoload -o