LEBRON, the statistical metric, stands for “Luck -adjusted player Estimate using a Box prior Regularized ON-OFF”, which is developed by the guys over BBall-Index.
Besides being an ON-OFF metric, LEBRON also includes box score elements for an impact score measured per 100 possessions. LEBRON uses weights from PIPM (Player Impact Plus-Minus) and luck adjusted RAPM.
To distinguish itself from other player impact metrics, LEBRON incorporates player role with stabilizing luck-adjusted RAPM calculations.