For a project created in a geospatial grid system, where certain parts are to be exported in a local grid (such as internal courtyards of a building), the local co-ordinates ".prj" exported with the .shp file in TBC 2024 seems to be incorrect:
PROJCS["IRENET95 Irish Trans. Mercator",GEOGCS["GCS_OSGB_1936",DATUM["D_OSGB_1936",SPHEROID["Geodetic Ref System 1980",6378137,298.257222101],TOWGS84[0,0,0,0,0,0,0],AUTHORITY["EPSG","6277"]],PRIMEM["Greenwich",0,AUTHORITY["EPSG","8901"]],UNIT["Degree",0.01745329251994, AUTHORITY["EPSG","9102"]],AXIS["Long",EAST],AXIS["Lat",NORTH],AUTHORITY["EPSG","4277"]],PROJECTION["Transverse_Mercator"],PARAMETER["False_Easting",600000],PARAMETER["False_Northing",750000],PARAMETER["Latitude_Of_Origin",53.5],PARAMETER["Central_Meridian",-8],PARAMETER["Scale_Factor",0.99982],UNIT["Meter",1,AUTHORITY["EPSG","9001"]],AXIS["East",EAST],AXIS["North", NORTH],AUTHORITY["EPSG","2157"]]
..it seems to be a mix of two diferent geospatial projection systems.
For reference, in earlier versions of TBC including 5.x for the same project settings and export settings the below ".prj" was exported and works in other applications when being used as substitute for the above ".prj":
PROJCS["Plane_Grid",GEOGCS["Plane_Grid",DATUM["WGS_1984",SPHEROID["World_Geodetic_System_1984",6378137,298.25722356301],TOWGS84[0,0,0,0,0,0,0]],PRIMEM["Greenwich",0.0], UNIT["Degree",0.0174532925199433]],UNIT["Meter",1]]