From the release notes it says they moved the highlight occurrences to a plugin in 13.12 but I cant find it anywhere.
So how do we enable it now? The section where it was in the settings is empty.
Plugins -> Manager -> Occurrence highlighting
...and Settings -> Editor -> Occurrences Highlighting (assuming the plugin is installed and enabled). I checked Windows: Its definitely there in 13.12.
It is a core plugin, so it should be installed always.