Nothing seems to be done in v4. Code to sax the metadataset index (or indexing model?) is commented out in org.ametys.web.frontoffice.AbstractSearchGenerator line 954
This is the content of the hit XML tag that I receive in the XSL of the service
<hit>
<score>6.6288896</score>
<percent>100</percent>
<title>p3</title>
<content>
<!-- INDEXED METADATA SHOULD BE HERE! -->
</content>
<content-name>nouveau-article-12</content-name>
<excerpt>ok!...</excerpt>
<type>page</type>
<uri>fr/p3</uri>
<sitename>www</sitename>
<sitetitle>Demo site</sitetitle>
<siteurl>http:</hit>
A new issue was open for 4.0
CMS-7182