SDPROTHEAD 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 "SD Monitor: Log Header Data" 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_SDPROTHEAD TYPE SDPROTHEAD.
The SDPROTHEAD table consists of various fields, each holding specific information or linking keys about SD Monitor: Log Header Data data available in SAP. These include VBELN (Sales and Distribution Document Number), PROTTYPE (SD Monitor: Log Entry Type), POSNR (Item number of the SD document), ETENR (Delivery Schedule Line Number)... 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. .