It’s wrapper is made from rice flour and filling is usually red bean paste (anko) with sugar. Many flavours are available but the most traditional are probably red or white bean paste, cinnamon, white or black sesame, and powdered green tea (matcha). I notice your package had a sticker saying “choco” (chocolate).

You may have notice that the sweets where wrapped like a present. That’s because they’re usually purchased by Japanese people when they travel as “omiyage” (meaning souvenir) for their family, friends, and most importantly coworkers. Whether traveling for business or pleasure purchasing “omiyage” is usually obligatory and often expensive, but also a beautiful tradition that Japanese delight in and it means there is always a pile of snacks beside the office coffeemaker.