The SE subpocket is predominantly occupied by single aromatic rings, while the FP subpocket shows both single aromatic and non-aromatic rings with different substitutions. Both subpockets show residual groups rich in nitrogen, oxygen, and halogen. The GA subpocket binds mostly benzene rings with oxygen-and halogen-rich residual groups. Both GA and FP also accommodate smaller linear fragments, which are mostly terminal fragments, since a large fraction of molecules are front pocket binders and thus, do not extend further into the back pockets. For B1 and B2, much less data is available (about 90 vs. 1,000-2,500 molecules per pocket), thus, the fragments are less representative for the chemical matter that could be accommodated by these pockets: The B1 subpocket pool contains many sulfonyl groups and is rich in halogen substitutions (e.g. trifluoromethyl groups), whereas the B2 subpocket shows a quite diverse set of ligands. An overview of the 50 most common fragments per subpocket is shown in Figure -S7. The identified common fragments are in good agreement with the representative scaffolds reported for the different KLIFS subpockets by van Linden et al. (Table in the original publication).