Questions & Answers about Paket kapı önünde bekliyor.
önünde = ön (front) + -ü (3rd person singular possessive: “its”) + -nde (locative: “at/in/on”).
So önünde literally means “at its front,” with “its” referring back to kapı.
When the locative suffix -de attaches to a stem ending in a vowel (here önü ends in ü), Turkish inserts an epenthetic n for easier pronunciation:
önü + de → önünde