Leave-Out Variance Component Estimation for Two-Way Fixed Effects Models // Implements leave-out estimation of variance components in two-way fixed effects models as an 'R' translation of the original 'MATLAB' package of Kline, Saggio, and Solvsten (2020) doi:10.3982/ECTA16410. The package includes graph-based connected-set pruning, leave-out bias correction, leverage computation by exact and randomized algorithms, fixed effect estimation helpers, and companion model-fit summaries for matched worker-firm panels in the spirit of Abowd, Kramarz, and Margolis (1999) doi:10.1111/1468-0262.00020.