June 19, 1865 represents the day slaves in Galveston, Texas learned of their freedom.
Though Juneteenth became a federal holiday in 2021, it has been an official holiday in Galveston, Texas since 1980 and has been celebrated informally since 1865.
Some fought long and hard, i.e. Ms. Opal Lee, for Juneteenth to become a federal holiday. But, some were happy with having it remain a community holiday without national fanfare.
(African American tradition is communal, so many prefer not to see tradition commercialized.)
At any rate, some welcome the day off; some use it to learn and celebrate community.
Juneteenth: Freedom Day!
Here are a couple of links on Juneteenth:
Setting the historical record straight
Sharing on food history and tradition