FMBCS_S_HEADER_EXT 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 "Budget localization fields (contained in table FMBH)" 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_FMBCS_S_HEADER_EXT TYPE FMBCS_S_HEADER_EXT.
The FMBCS_S_HEADER_EXT table consists of various fields, each holding specific information or linking keys about Budget localization fields (contained in table FMBH) data available in SAP. These include DUMMY_EXT (General Flag)... 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. .