This page includes a Meta field as an example of one which might be set up locally. In this case, it's "color", but in another case it could be "product-code", "location", "price" or any number of other tags.
This color field contains the search code "RTest Good 170" (without the spaces). If you search on that code and find this page, the search engine is indexing the contents of that field.
Some search engines also allow you to specify only that tag, usually by typing in the search field, like this: color:rtest.