proj4 string obtained by running "projinfo epsg:2169" using a PROJ 9.3 installation

epsg:2169.txt

PROJ.4 string:
+proj=tmerc +lat_0=49.8333333333333 +lon_0=6.16666666666667 +k=1 +x_0=80000 +y_0=100000 +ellps=intl +towgs84=-189.6806,18.3463,-42.7695,-0.33746,-3.09264,2.53861,0.4598 +units=m +no_defs +type=crs

WKT2:2019 string:
PROJCRS["LUREF / Luxembourg TM",
    BASEGEOGCRS["LUREF",
        DATUM["Luxembourg Reference Frame",
            ELLIPSOID["International 1924",6378388,297,
                LENGTHUNIT["metre",1]]],
        PRIMEM["Greenwich",0,
            ANGLEUNIT["degree",0.0174532925199433]],
        ID["EPSG",4181]],
    CONVERSION["Luxembourg TM",
        METHOD["Transverse Mercator",
            ID["EPSG",9807]],
        PARAMETER["Latitude of natural origin",49.8333333333333,
            ANGLEUNIT["degree",0.0174532925199433],
            ID["EPSG",8801]],
        PARAMETER["Longitude of natural origin",6.16666666666667,
            ANGLEUNIT["degree",0.0174532925199433],
            ID["EPSG",8802]],
        PARAMETER["Scale factor at natural origin",1,
            SCALEUNIT["unity",1],
            ID["EPSG",8805]],
        PARAMETER["False easting",80000,
            LENGTHUNIT["metre",1],
            ID["EPSG",8806]],
        PARAMETER["False northing",100000,
            LENGTHUNIT["metre",1],
            ID["EPSG",8807]]],
    CS[Cartesian,2],
        AXIS["northing (X)",north,
            ORDER[1],
            LENGTHUNIT["metre",1]],
        AXIS["easting (Y)",east,
            ORDER[2],
            LENGTHUNIT["metre",1]],
    USAGE[
        SCOPE["Engineering survey, topographic mapping."],
        AREA["Luxembourg."],
        BBOX[49.44,5.73,50.19,6.53]],
    ID["EPSG",2169]]