editmesh_bevel.c:

void MESH_OT_bevel(wmOperatorType *ot)
{
  ...

  RNA_def_pointer(ot->srna, "prwdgt", "ProfileWidget", "", "Widget for editing profile path");
  ...
}

static bool edbm_bevel_calc(wmOperator *op)
{
  ...
  const PointerRNA prwdgt_ptr = RNA_pointer_get(op->ptr, "prwdgt");
  ...
}


rna_profile.c:

static void rna_def_profilewidget_points_api(BlenderRNA *brna, PropertyRNA *cprop)
{
  StructRNA *srna;
  PropertyRNA *parm;
  FunctionRNA *func;

  RNA_def_property_srna(cprop, "ProfilePoints");
  srna = RNA_def_struct(brna, "ProfilePoints", NULL);
  RNA_def_struct_sdna(srna, "ProfileWidget");
  RNA_def_struct_ui_text(srna, "Profile Point", "Collection of Profile Points");
  ...
}