These features are not enabled by default, but is very easy to do so from Administration.
Experimental text extraction
Edit experimental.text.extraction configuration property and set to true.
To enable this feature you have to edit the repository.xml and repository/workspaces/default/workspace.xml and remove all contents at textFilterClasses parameter from SearchIndex section. Be sure to stop OpenKM before editing these files. Once modified and started OpenKM again, the new uploaded documents will be indexed with the new experimental text extraction mechanism.
From Administration > Repository view you would be able to see a property called text where the document extracted text is store. This way you can see exactly which has been indexed by OpenKM search engine. Also from Administration > Database query you can look for text extraction problems executing this JDBC query:
select * from OKM_ACTIVITY where ACT_ACTION='MISC_TEXT_EXTRACTION_FAILURE'
Experimental mobile version
Edit experimental.mobile.version configuration property and set to true.