rgsregions adds the source and background extraction region extensions to the source list. For each relevant source position there is one region in the spatial plane and one region per (specified) reflection order in the energy plane. The relevant source positions refer to the sources marked for processing. The spatial background region covers the entire exposed surface of the focal plane, except for a buffer zone around the position of each source marked for exclusion. Note that the source selections (for processing and exclusion) are determined by the procsrcsexpr and exclsrcsexpr parameters and recorded in the SRCLIST table as selection flags. To sanction the existing settings of these flags supply empty strings for these parameters. A spatial background region cannot be defined for HTR mode data; there is instead a set of order-specific background regions in the energy plane for each selected source.