This is to get more information about the selected tool, since the "tool_id" is not enough in some cases, such as differentiating road prices for example.
current_tool().get_obj_desc_x()
(http://files.simutrans.com/index.php/apps/gallery/preview/1048?width=1300&height=1300&c=c1c2420670fbb9b701c70dd36cc5210a&requesttoken=acJNPUhRb%2B7gj86EholtE6JbwJ%2BE5Wi6nKuUxPYQGxw%3D%3ADo8YcQxhP4%2BS2L3izu0kIYkMpvDlshHM8ebwgpBGSmw%3D)
What would you like to do with this information?
In the tutorial, it is to be more specific with the tool that needs to be used ... for example, to obtain the name of the object, to know if the station is of passengers or merchandise, to know the maximum speed of the road ... of this way you have more control of the tools when restricting an action.
I guess it's hard to implement? . ???
yes, exactly. There is no interface in the program to get these desc-objects from the tool. Each tool does this slightly differently.