I've created a Test space under Main, to result
Than try to export the Main page. Sometimes it let's you export it, so try several times. I couldn't find exactly how to reproduce it, but you will get main-search.png
I reproduced it over 4 times.
- Open the main wiki page: http://localhost:8080/xwiki/bin/view/Main/
- Go to "more menu" -> "Export" -> "Other formats"
- Open the tree, click on select "none" to uncheck all and check "Solr Search"
- Click on "Export as HTML"