RDEFAULT_DATA is a standard SAP Structure so does not store data like a database table does. It can be used to define the fields of other actual tables or to process "Default: All Data Relevant for Default" Information within sap ABAP programs. This is done by declaring abap internal tables, work areas or database tables based on this Structure. These can then be used to store and process the required data appropriately. i.e. DATA: wa_RDEFAULT_DATA TYPE RDEFAULT_DATA.
The RDEFAULT_DATA table consists of various fields, each holding specific information or linking keys about Default: All Data Relevant for Default data available in SAP. These include MHND (), KNB1 (), VDDUNN (), VDDEF_COUNTER ()... See below for full list along with technical details, documentation, text table, check tables, foreign key relationships, conversion routines, relevant tcodes and example ABAP select code etc. .