Are you referring to the term keyword that shows up in the definition?

The term keyword is a bit of a red herring, but the basic
functionality seems to work for any link or multilink field.

I just tried the following patch to the demo
classic tracker:

                db_klass string:status;
                 db_content string:name;">
   <th i18n:translate="">Status:</th>
-  <td metal:use-macro="search_select_translated">
+  <td metal:use-macro="search_select_keywords">
     <tal:block metal:fill-slot="extra_options">
       <option value="-1,1,2,3,4,5,6,7" i18n:translate=""
               tal:attributes="selected python:value ==
'-1,1,2,3,4,5,6,7'">not resolved</option>

and I was able to generate the equivalent of "not resolved"
using or's between all of the statuses except for resolved.

What exactly "ties" this to the tracker?