/usr/share/metview/etc/XsectDef is in metview-data 4.8.0-4.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 | PM_XSECT; Metview; Specific Application
{
   DATA
      [
         interface       = icon,
         class           = GRIB,
         exclusive       = false,
         help            = help_data,
         help_directory  = '/System/Defaults',
         help_name       = Data for XSection,
         help_class      = RETRIEVE,
         help_definition = ( RETRIEVE, TYPE = FC, LEVTYPE = PL,
                             PARAM = T, DATE = '-1',
                             LEVELIST = 1000/850/700/500/400/300,
                             STEP = 12, GRID = 1.5/1.5 )
      ]
   { @ }
   LINE
      [
         help         = help_input,
         input_type   = line,
         input_window = '/System/Defaults/Input Window'
      ]
   {
      *
      /
   } = 0./-180./0./180.
   PRESSURE_LEVEL_AXIS
   {
      LINEAR
      LOG
   } = LINEAR
   BOTTOM_PRESSURE
   {
      *
   } = 1015.0
   TOP_PRESSURE
   {
      *
   } = 10.0
   WIND_PARALLEL
   {
      ON
      OFF
   } = ON
   WIND_PERPENDICULAR
   {
      ON
      OFF
   } = OFF
   WIND_INTENSITY
   {
      ON
      OFF
   } = OFF
   WIND_HORIZONTAL_COMPONENT
      [ visible = false ]
   {
      PERPENDICULAR   ; PER
      PARALLEL        ; PAR
      INTENSITY       ; INT
   } = PAR
   INTERPOLATE_VALUES
   {
      YES
      NO
   } = YES
   LNSP_PARAM
   {
      *
   } = 152
   U_WIND_PARAM
   {
      *
   } = 131
   V_WIND_PARAM
   {
      *
   } = 132
   W_WIND_PARAM
   {
      *
   } = 135
}
 |