A qgis_result object is a list that, next to the output elements, also contains other elements that can be useful in scripting. Several of these can be extracted with convenience functions: the exit status of the process, standard output and standard error of 'qgis_process', arguments passed to 'qgis_process'.
Other topics about programming or debugging utilities: qgis_run(), qgis_tmp_file(), qgis_unconfigure(), qgis_using_json_input()
Other topics about accessing or managing processing results: qgis_as_raster(), qgis_as_terra(), qgis_clean_result(), qgis_extract_output(), st_as_sf, st_as_stars