index the username field for fulltext search?

This is neither a bug report nor a feature request, just a question (well really, two questions):

1. Is the username field indexed for fulltext search?

2. If not, should it be?

The story (from https://hypothes-is.slack.com/archives/programs/p1480540102000177):

[1:10]
also, @judell what i mean is showing my replies to others annotations when you search for me as a user

[1:11]
not replies to my annotations, which is what we have now (but will not have with AP at first)

[1:15]
@jeremydean your question prompted me to try this experiment:

https://hypothes.is/search?q=url%3Ahttps%3A%2F%2Fwww.literacyworldwide.org%2Fblog%2Fliteracy-daily%2F2016%2F02%2F03%2Fknowing-the-difference-between-digital-skills-and-digital-literacies-and-teaching-both+jeremydean

My theory of operation here: Combine a uri query with a freetext query for `jeremydean` -- seems like it should work, since I thought the user field was indexed in ES, but seems like it does not work. @arti is my theory wrong or should I investigate?

arti [1:19 PM]
not sure Jon - something you might want to ask Robert or Nick

judell [1:24 PM]
Evidently it is not indexed. Compare https://hypothes.is/users/jeremydean?q= vs https://hypothes.is/search?q=jeremydean. If the user field were indexed, "Knowing the Difference" would appear in both result sets. Indexing the username for fulltext search might be a useful tweak. I could swear it used to work that way, but maybe not.