IRLOTH 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 Reference Location (Table) With Hierarchy Level" 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_IRLOTH TYPE IRLOTH.
The IRLOTH table consists of various fields, each holding specific information or linking keys about Technical Reference Location (Table) With Hierarchy Level data available in SAP. These include MANDT (Client), TRPNR (Reference functional location), MLANG (Primary language for object texts), TPLKZ (Functional location structure 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. .