What was the meaning of a novel's overt and understated lines? How could they be distinguished? thanks

The overt and hidden lines of a novel referred to the plot clues that were clearly displayed and hinted at in the plot of the novel. Bright lines referred to the plot clues that the author clearly expressed at the beginning or in the middle of the novel, which the readers could directly know through words or dialogue. For example, at the beginning or in the middle of the novel, the protagonist's background, personality, relationships, and other plot clues directly promoted the development of the story. The dark lines referred to the plot clues that the author expressed at the end of the novel or in the following plots through hints, metaphor, hints, and so on. The readers needed to use other means such as the words and deeds of the characters, the description of the environment, and the plot twist to speculate and guess the plot of the hidden line. For example, the plot at the end of the novel that revealed the secret, danger, or ending of a certain character was a dark line. The main way to distinguish between open and dark lines was to look at the author's expression in the plot of the novel. The bright lines were the plot clues that the author directly showed, while the dark lines were the plot clues that were expressed through hints, metaphor, hints, and so on.