ACT_CUSTDATA_ST 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 "Structute for activity CI" 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_ACT_CUSTDATA_ST TYPE ACT_CUSTDATA_ST.
The ACT_CUSTDATA_ST table consists of various fields, each holding specific information or linking keys about Structute for activity CI data available in SAP. These include ACTIVITY (Activity number in network and standard network), OBJNR (Object number), DUMMY_CI_AFVU (Single-Character Indicator)... 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. .