It does not provide a launcher, so I could only start it from the terminal and it only opens .stl-files dragged to it. It did not find any of my .stl-files with the builtin file browser. The .stl-viewer itself is not bad. The option to provide a background image works surprisingly well for contrast.
Does what it says on the can. What I've been looking for ...a simple viewer. Mint 20.1 latest updates as of 15 Mar'21
Renders STL's like a champ. Crashes on startup occasionally and doesn't have an icon in the start menu, but it does render STLs.