We speak of a large report with many pages and visualisations on it.
The only quite obvious idea I have is to open each page and review all the visualisations and text areas
manually but I wonder if there can be a script that would help with the task.
You might be able to get some of this information out of the Spotfire database.  I'm still on version 10.3, not the newer version, but I know that they are tracking more and more user actions in later versions.
How to identify unused columns/calculated columns present in the report (IronPython perhaps?)?