Table meta information

**What's your use case?**

In general: I would like to attach meta information to a table, which can be used in the following widgets.

I have seen that Table has `attributes`. But I am not sure what you have provided that for and if I can use it for my purposes.

Also, the table loses its attributes in some widgets that create completely different output data from the input data (like owgroupby or owpivot). But for me it is quite essential that the table keeps the information.

My case in concrete terms:
In my importer, I would like to append the file name to the table so that the file name can be displayed in a visualisation widget, e.g. as a title. Even if owgroupby changes the data in between, the file name should still be kept.

**What's your proposed solution?**

No real proposal, but at the moment I'm using the following prototype approach:

I have monkeypatched orangewidget.utils.signals.Output.send so that the table attribute "meta_information" (dict that also includes the file name) is inserted into the output data if it is present at the input.
This way I make sure that the information is passed on, regardless of what the widget does.

**Are there any alternative solutions?**

I don't know. Ensure that `attributes` are passed on for all widgets?

To summarise:
- Does such a behaviour already exist in Orange?
- Are you interested in including it in Orange?
- Do you have a better solution?