*[${field}$]* is a special variable setup by FieldTag.java which assigns things like so

1. *[${field.name}$]* is assigned the 'entity.name'
2. *[${field.id}$]* is assigned a valid html form of 'entity.name' which in this case is the same
3. *[${field.i18nKey}$]* is assigned the string 'entity.name' (may seem repetitive but for arrays, this differs from field.name)
4. *[${field.flash}$]* is assigned the value that flash scope has for variable 'entity.name'
5. *[${field.error}$]* is assigned the error value from validations flash for variable 'entity.name'
6. *[${field.errorClass}$]* is assigned the css class if there was an error in *[${field.error}$]*
7. *[${field.flashOrValue}$]* is assigned the flash first if exists and next the original value(ie. if you were editing)
8. *[${field.valueOrFlash}$]* is assigned the value first if exists and next the value from flash scope

To make things easier for the developer, this field variable gets passed to the body of the field tag as well so you can also use the field variable not only in field.tag but in the body that is passed in to keep things very generic and cut/paste like for future fields. cool, right? well, I thought so