The District 10 female was the female tribute from District 10 who participated in the 75th Hunger Games. She was also the victor of an unspecified Hunger Games and presumably trained other tributes as a mentor.
After her victory, she was assigned a mentor for future District 10 tributes. Since her age is said older than the District 10 male victor and tribute for the 75th Hunger Games, it’s possible that she may have mentored him to victory. Alongside that, she may have mentored the District 10 tributes for the 74th Hunger Games.
75th Hunger Games
In the book, during the chariot rides, she was dressed in a ridiculous looking cow outfit, with flaming belts, which unintentionally appeared as if the cows were broiling themselves. Unlike the film adaptation, she is seen behind Finnick, when he is talking to Katniss. She is wearing a Greek gown, the top part is dark blue, as the bottom fades into a lighter blue.
She wore a black leather suit and watched each tribute's interviews with Caesar, until hers. She joined hands with the other victors as a sign of rebellion against the Capitol, which angered them greatly.