You are probably most familiar with search highlighting when you use an Internet search engine such as Google. Most search results come back with a snippet of text from the site containing the word(s) you search for, highlighted. Solr can do the same thing. In the following screenshot, we see Google highlighting a search including Solr and search (in bold):
To conserve screen space, you might even use this feature to simply tell the user that there was a match in certain fields without showing a highlighted value. This could make sense if there are many metadata fields. Nevertheless you would still likely highlight some.
Admittedly the MusicBrainz dataset does not make an ideal example to show off highlighting because there's no substantial text, but it can still be useful, nonetheless.
The following is a sample use of highlighting on a search for Corgan in the MusicBrainz's artist dataset. Recall that the /mb_artists request handler is configured...