FRMLS_EXPL_IO 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 "IO Structure for Explosion-Relevant Views" 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_FRMLS_EXPL_IO TYPE FRMLS_EXPL_IO.
The FRMLS_EXPL_IO table consists of various fields, each holding specific information or linking keys about IO Structure for Explosion-Relevant Views data available in SAP. These include LINENO (General Counter), LINEMOD (Processing Status/Mode of a Record/Step Loop Line), MANDT (Client), RECN (RMS-FRM: Object Identifier)... 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. .