January 2030 has 31 days. The 1st falls on a Tuesday and the 31st on a Thursday, so the grid runs to 5 rows.
Federal holidays this month: New Year's Day on January 1 (a Tuesday), and Martin Luther King Jr. Day on January 21 (a Monday).
Holiday names print inside the day cell, wrapped to fit rather than running across the rule into the next day.
The week runs Sunday to Saturday, the usual US arrangement.