PROJ_UPDATE_RELEVANT 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 "Fields from PROJ (sim.vers.) that are relevant to the update" 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_PROJ_UPDATE_RELEVANT TYPE PROJ_UPDATE_RELEVANT.
The PROJ_UPDATE_RELEVANT table consists of various fields, each holding specific information or linking keys about Fields from PROJ (sim.vers.) that are relevant to the update data available in SAP. These include POST1 (PS: Short description (1st text line)), KIMSK (Selection mask for WBS element short IDs), AUTOD (Automatic value transfer from WBS element to project def.), STSPD (Status profile for project definition)... 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. .