The AWB enables customizing of format definition fields in certificate, key, CRL and CIL procedures. Read more, for example, here: Policy tasks in Certificate Manager, where this is used in various instructions.
Once a format has been selected, you can customize the set of format definition fields and modules. Here is an example with the certificate format rfc5280. The new values will take precedence over the values in the format file, but the format file will not be affected by these changes.