UPP_YS_API_HEAD 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 "Header Combination" 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_UPP_YS_API_HEAD TYPE UPP_YS_API_HEAD.
The UPP_YS_API_HEAD table consists of various fields, each holding specific information or linking keys about Header Combination data available in SAP. These include CHAVLEXT (Field for any characteristic value (external display)), TXTLG (Long Description), KEYWORD (Long Description), HIDE (Entry Is Hidden in Front End)... 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. .