Hi MaxDelphi,

a good help here is the documentation for searching: https://www.novell.com/documentation/vibe_onprem31/vibeprem31_user/data/informed_search.html#informed_search_basic .

Unfortunately, it does not list the field name for searching tags, since that is provided by the search interface itself. We once pulled an entry in search index notation and found the fields you can access. The one for tags is "_tagField", so your search query might need to look something like this:

<QUERY>
  <OR>
    <FIELD fieldname="_tagField" exactphrase="true">
      <TERMS>TheTagWeSearchFor</TERMS>
    </FIELD>
    <FIELD fieldname="_tagField" exactphrase="true">
      <TERMS>AlternativeTag</TERMS>
    </FIELD>
  </OR>
</QUERY>

Other fields can be helpful too, like "_family" for searching only an entry type family (see documentation on creating custom entry types for examples).

The structure of the query is pretty much described in the doc you linked, meaning you probably won't find more on it without some analysis. However, the best mindset to approach this is "Look at the web based search. You should be able to place the same search queries. The only issue should be finding the field names. :)

HTH!
Christian