How Does ‘The Hunger Games: Mockingjay — Part 1’ End?

Source: https://collider.com/the-hunger-games-mockingjay-part-1-ending-explained/

Katniss Everdeen's version of "The Hanging Tree" in The Hunger Games: Mockingjay - Part 1 was inspired by Lucy Gray's song, with some changes made to inspire rebels.

Source: https://screenrant.com/hunger-games-ballad-songbirds-snakes-hanging-tree-katniss/

Knowing that losing Prim would break Katniss's spirit, Coin gave the order to kill Prim when she no longer needed Katniss to be the Mockingjay.

Source: https://www.cbr.com/hunger-games-mockingjay-glosses-over-katniss-suicide-attempt/

That adaptation was shelved owing to an ever increasing budget and it would be Francis Lawrence (The Hunger Games: Mockingjay Part 1 and 2) that would eventually take the director's chair with Smith in the main role.

Source: https://www.joe.ie/movies-tv/will-smith-netflix-i-am-legend-784939

The Hunger Games: Mockingjay Part 2 - November 20, 2015.

Source: https://collider.com/the-hunger-games-movies-in-order-how-to-watch/