smart collection criteria

AAARRRRGGHH!  I'm not interested in searching regarding any plug-in.  Plug-ins entered the conversation by another explanation.  I was trying to find a useful way to use this exported feature of a smart collection, that's all.  Nothing whatsoever to do with plug-ins, but I gather from earlier answer that it's only useful for plug-ins which makes it totally not useful for me.

If I understand you correctly, that's disappointing for sure and makes the "exported" option virtually useless.  Adobe should somehow label or make clear that the "exported" feature ONLY applies to plug-ins.  I have several plug-ins installed and fail to see how an exported search based on them would be of any use. 

So, you're telling me that when I set the smart collection rule for "exported", then "isn't empty", and I  get a result of 4605 images, that means that of all the images I've exported (many more than 4605), that 4605 of them had some sort of plug-in used?  What then am I being told when I set the rule for "is empty" and get a result of almost my whole catalog?  What good is that?  I've not used plugins on my entire catalog!  Seems like bottom line is I'm S.O.L for utilizing this export feature for anything useful.  Not an answer I was hoping for but thanks for the help and now I can go on with other work.  

If you mean literally the word "exported", no I did not as it seems redundant to put exported there when one is searching for export as chosen from the dropdown.  What I am trying to learn is what criteria can be used to limit define the export smart collection.

My first puzzle is “what is or is not empty” as regards an export.  I made a test smart collection and first used “export isn’t empty” as shown here

The result was 4605 images.  I then changed the criteria to “export is empty” and the number went to 589,771 which is almost my whole catalog of 594,376.  So I guess LR somehow knows if a file has been exported.  Great except, when I activate the “isn’t empty” it gives a smart collection of 4605 and when I look at the images, the collection cannot contain all of the images I’ve exported simply because I exported some over the past week, none of which are there.  So what is the trigger for exported empty or not?

Moving on from that is what led me to try and find help with the additional exported rules which have descriptions such as "contains words", "starts with", etc.  What is it looking to start with or what words to contain????? 

I’ve tried using the “contains words” putting in dates & file names – no luck.  I tried using “starts with” using the first characters of file names – no luck.  What is it looking to see what it starts with?

No matter what I put in the last field to the right, the result is zero files selected.

it's one of the criteria options in the smart collection dropdown, see above screen grab

Thanks for trying.  I appreciate your time but that article does not cover the export option and is no help.  That's what I meant when I said I could find no documentation.  Lots of info on the most basic stuff like stars and colors, but nothing regarding export criteria.