The format of the fragment file

Your work is especially helpful! I found that the two fragments in the SDF file you provided are complete molecules with 3D structures. If I have two fragments, must they also be complete molecules and 3D structures? And I want to ask are fragments from ligands in the original PDB protein structure broken up?
My fragment molecule for example: c1ccc(*(=O)(O)NC(C)(C)C)cc1*”，*c1n*nn1
