STL Import & Export Unsigned

SU Make 2017. In Extension Manager, STL Import & Export is Unsigned. The loading policy is checked for unrestricted.
The extension has been installed and un-installed twice. How do I get a signed STL extension?

This wasn’t a problem in SU 2015 and 2016.

We know. It needs to be signed and re-uploaded. An issue has been logged:
GitHub: sketchup-stl, Issue #161, Can we get this signed for 2017? (Jim Foltz)

You update the extension after a signed version is posted. Until then, you use the unsigned version (as everyone has for years.)

Then it will be loaded. Read the page above for instructions on how to use the extension (ie how to export and import.)

Because those versions do not use extension signing. It is a new feature for SketchUp 2017+.