STPRPS_EXT_IN 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 "structure for extension in wbs" 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_STPRPS_EXT_IN TYPE STPRPS_EXT_IN.
The STPRPS_EXT_IN table consists of various fields, each holding specific information or linking keys about structure for extension in wbs data available in SAP. These include VALUEPART1 (Data part of BAPI extension parameter), VALUEPART2 (Data part of BAPI extension parameter), VALUEPART3 (Data part of BAPI extension parameter), VALUEPART4 (Data part of BAPI extension parameter)... 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. .