ITOBEXT 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 "Technical Objects in PM: Data with External View" 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_ITOBEXT TYPE ITOBEXT.
The ITOBEXT table consists of various fields, each holding specific information or linking keys about Technical Objects in PM: Data with External View data available in SAP. These include GEWRK (Main work center for maintenance tasks), WERGW (Plant associated with main work center), TPLMA (Functional Location Label)... 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. .