पाणिनीविरचिता
ञ्ईत् in present tense has क्त suffix. Here ञ्ई is इत्. क्त would have otherwise been indicated past tense - but this rule makes it present tense. For example, ञिमिदा क्त - मिद् त् - मिद् न् (इट् is barred due to आदितश्च ) - मिन्न सु - मिन्नः.