ZF-7349: Zend_Reflection_File does not reflect interfaces. Zend_CodeGenerator cannot generate interfaces.
The tokenizer in Zend_Reflection_File ignores T_INTERFACE so it is not possible to reflect interfaces within files at the moment. Zend_Reflection_Class inherits ReflectionClass thus it should be possible to reflect interfaces.
Zend_CodeGenerator_Php_Class assumes that Zend_Reflection_Class is always a class. So it is not possible to generate an interface.