What is the opening supplication (Duʿāʾ al-Istiftāḥ) and what is its evidence from the Sunnah?

The opening supplication (Du'a al-Istiftah) is what is recited after the opening takbir (Allahu Akbar) and before seeking refuge (Ta'awwudh) to recite Al-Fatiha. It has been authentically reported from the Prophet, peace be upon him. Some of its forms include: "O Allah, distance me from my sins as You have distanced the East and the West. O Allah, cleanse me of my sins as a white garment is cleansed from dirt. O Allah, wash away my sins with water, snow, and hail." And among them: "Glory be to You, O Allah, and with Your praise; blessed is Your Name, exalted is Your Majesty, and there is no god besides You." And among them: "Indeed, I have turned my face toward Him who originated the heavens and the earth, inclining toward truth; and I am not of those who associate others with Allah. Indeed, my prayer, my rites of sacrifice, my living and my dying are for Allah, Lord of the worlds. No partner has He. And of this I have been commanded, and I am of the Muslims."