The indirect effect measures how much the independent variable influences the dependent variable through a mediator (intervening) variable.
Pearl, J. (2022). Direct and indirect effects. In H. Geffner, R. Dechter & J. Halpern (Eds.), Probabilistic and Causal Inference: The Works of Judea Pearl (pp. 373-392). ACM Books. https://doi.org/10.1145/3501714.3501736