I forgot to mention that out of 100K queries, there were 80287 unique queries.
    29667 via web
    70333 via api

I should have distinguished api from web before.


*- filter the term "quot" from queries*

quot or " ?

just quot—it's weird. Those queries had to go through a couple of incompatible filters to end up like that. 

 
*- filter 14###########: from the front of queries*

UNIX time? 1437794758

Very nice! That would explain why they all start with 14 and are that length. But if they are epoch seconds, they don't make sense. Here's the range over the 7000 instances:

1410632926515 -> Sat, 13 Sep 2014 18:28:46 GMT
1440274360664 -> Sat, 22 Aug 2015 20:12:40 GMT

That's from last year through next month. Makes no sense! All of these queries were within an hour on one day.
 

*- replace _ with space in queries*

Do you have actual URL of the search? [[Special:Search/this_format]] is supposed to ignore underscores already
 
Also, a full text search URL containing "search=" but not "fulltext=" is first of all a title search (the aim is to be redirected to the title if it exists).

I don't have access to the URL at the moment, just the elastic search logs. I limited my initial investigation to things marked as full text ("full_text search for ...")

And some of the underscores are in the weird boolean queries.

For the incremental searches, do we know if all browsers which integrate a Wikipedia search bar use the correct API for suggestions?

I don't know, but I'll keep that in mind.

Looking more carefully at the logs, I didn't distinguish web searches and api searches, which I should have. The two most obvious incremental searches were via api.. which makes sense.

More later...

—Trey