Geoffrey De Smet Yes I tested online as you told me the file:// deactivates the script. The test is at http://docs.jboss.org/hibernate/ogm/secret-test/html_single/

There seem to be several things going on.
When I look at http://docs.jboss.org/optaplanner/release/6.2.0.Final/optaplanner-docs/html_single/index.html your script version is different (that's not non tag manager version)

On http://docs.jboss.org/hibernate/ogm/secret-test/html_single/ I don't see a abine.stub.Google Analytics script in the headers like in Optaplanner's case. Also there are a lot of other tracking scripts which are inserted by the docs.jboss.org Apache I suppose.

I am attaching the index.html that I generate that does not have the additional scripts.