Search GitHub for "SketchUp Slicer." Some developers have forked the original code to make it compatible with SketchUp 2023-2025. These are usually free and open-source.
Ultimate Guide to Slicer 5 for SketchUp: Free Download and Tutorial slicer 5 sketchup plugin free download
The original Slicer 5 was written for SketchUp 2015–2017. If you are using SketchUp 2020 or newer , the original version will likely crash or fail to load. Search GitHub for "SketchUp Slicer
Advanced tips on for solid inspection.