Short answers, pulled from the story.
Boxing Day takes its name from the Christmas box, a gift or gratuity given to tradespeople and servants. The Oxford English Dictionary's earliest British attestation dates to 1743. Servants who worked on Christmas Day were traditionally given a box of gifts, bonuses, and food by their employers on the 26th of December so they could visit their own families.
Boxing Day is a public holiday in the United Kingdom, Australia (except South Australia), Canada, New Zealand, Nigeria, Trinidad and Tobago, and Hong Kong, among other Commonwealth nations. South Africa observes the same date as the Day of Goodwill, a name adopted in 1994.
Boxing Day became a bank holiday in the United Kingdom (outside Scotland) in 1871 under the Bank Holidays Act of that year. In Scotland, it was added as an additional bank holiday in 1974 by royal proclamation under the Banking and Financial Dealings Act 1971.
The Boxing Day Test is a cricket test match traditionally opened on the 26th of December at the Melbourne Cricket Ground by the Australian cricket team. The Australian Cricket Board formalized the tradition in 1980, though test matches had occasionally been held at the MCG around Boxing Day before that year.
Black Friday promotions contributed to a marked decline in traditional Boxing Day sales in both countries. In Canada, the shift accelerated from 2013 onward. In the UK, November retail sales exceeded December retail sales for the first time in 2015, and a retail analysis firm recorded a 9.8 percent drop in British store traffic on Boxing Day in 2019 compared with 2018.
Costumed Gombey dancers perform throughout the island of Bermuda on Boxing Day. The tradition is believed to date to the 18th century, when enslaved people were permitted to gather at Christmas.