In the above TOC, is it possible to remove these plus and minus icons? Also, where is the code available for this setting in generated file. Is it in css or js? This is the file generated using Robohelp 2019 version.
Classic or new UI? What layout are you using?
You can remove or change these icons in the output definition. Select the desired skin and click "Edit". The skin editor opens. There, in the section TOC, the used images are listed and can be changed. The screenshot is from the new UI, but it works similar in RH Classic. It just looks a bit different.