Attribute User text does, and allows you to select a CSV or CST file (haven’t tested cst just csv but it presumably works).
However the Import for Document user text only allows you to import from 3dm files.
Also, when you finally do get key value pairs inserted, the display area of the panel changes the import order the second you leave the panel and come back. Clicking on Key or Value will sort by the column, but there’s no way to get back to the order that was created initially.
I set up a whole mess of fields in excel and saved as CSV for use in a title block template, and that’s what uncovered this.
It’s very difficult to set text fields inside a block from Attribute User Text fields attached to the block, as the UI wants you to be able to select an object, which you can’t do when editing the block in place. The only workaround I’ve found is to just put a text object someplace external to the block, then user the FX button in that text object’s editor to select the block in order to get the guid populated correctly into the text field, then copy that and go back into edit block in place and manually paste the guid portion and edit the pasted text for the specific field. While it works, it’s way too cumbersome.
Finally, there’s an issue with using the user text fields in general, as if you hand type them in, or copy paste the guid from the object properties, the dialog insists on “smart formatting” the " character, and they don’t work with leading and trailing double quotes. While there are times when one might want leading and trailing quotes for aesthetic purposes, there should be away to enter a non leading or trailing quote in the dialog, or just make it take either or when evaluating the text.