ABC_F_KEY 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 "TPL: Key Fields for Logical Functions in Environment" 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_ABC_F_KEY TYPE ABC_F_KEY.
The ABC_F_KEY table consists of various fields, each holding specific information or linking keys about TPL: Key Fields for Logical Functions in Environment data available in SAP. These include ENVIRONMNT (Valid Environments), LOG_FUNC (Logical Function Name)... 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. .