Updated project metadata. iBench is an open-source tool that provides enhanced validation of Mass Spectrometry identification methods. For this project, iBench was applied to Percolator rescored results from Mascot searches from a tryptic digestion of the K562 proteome, HLA-I immunopeptidome experiment, and synthetic peptide libraries. Here we provide the Mascot search results which were benchmarked as well as the original searches used to generate the ground truth identifications. These search results were generated by reprocessing RAW data from the PXD031709, PXD034056 and PXD031812 repositories.