Q: Why a search here?
A: Elasticsearch GET API doesn't support stored or scripted fields, have to go through the search API

Q: Well then why didn't you use a searchSource?
A: It seemed wasteful to start up a temporary indexPattern and searchSource for one request. I would need to new up an indexPattern as the existing one could match some range of indices, and I need exactly one index. The indexPattern that does get loaded here is only used for formatters and scripted fields retrieval.

This isn't actually being compiled. Also, there doesn't appear to be any rules in plugins/doc/styles/main.less.