Download the .zip file and do not unpack it. In Blender open Edit > Preferences > Add-ons, click the drop-down arrow in the top-right corner and choose Install from Disk (in Blender 4.0 and 4.1 the button is called Install), then pick the downloaded file. Tick the checkbox next to Mesh: SKAVA Collision Mesh Generator Pro to enable it. Press N in the 3D Viewport and open the SKAVA tab in the sidebar.

The product page lists compatibility up to Blender 4.5. Newer versions are not listed.

It generates collision meshes for selected objects: select a mesh, choose the target engine (Unity, Unreal or Both), the collision type and a quality preset, and click Generate Collision. Process Selected Objects runs it on several objects at once.

Box, Sphere, Capsule, Convex (a single convex hull), Compound (several convex hulls for concave shapes) and Mesh (a decimated copy of the original, for terrain and complex static objects).

According to the documentation: Mobile allows up to 64 vertices per hull and 4 hulls, Standard 128 and 8, High 255 and 16, Ultra 512 and 32.

The product page lists the license as GPL.