Nanxiang Steamed Bun Restaurant Opens in Shanghai
ESTIMATED75% CONFIDENCEWikipedia[1] states "It was established in 1900" and gives no month or day, so the pin sits on that year's last day. It is placed at a Shanghai branch of the restaurant rather than the original premises.
The house that made xiaolongbao a Shanghai export was established in 1900, selling the thin-skinned soup dumplings that had been developed in Nanxiang town on the city's edge a couple of decades earlier. Queues for them became a fixture of the old city, and the name is now on branches across Shanghai and abroad.