In Sketchup 2015, it worked fine installing an extension with the .rbz file ending. However I now installed Sketchup 2016, and sketchup is doing it incorrectly, and even tells me everything went fine when installing, but then it simply fails to show the plugin in the list or toolbar.
Basically it unzip the plugin incorrectly, which results in it not finding it… If I move the plugin manually it starts working. So this is a bug in Sketchup 2016, even if the .rbz somehow is invalid, it should at least tell me so.
The plugin in question: https://github.com/JoakimSoderberg/sketchup-svg-outline-plugin
(I am not the author, I simply made it work for Sketchup 2014+)
Here is a step by step description on how Sketchup is lying to me:
… Turns out since I am a new user I could not post more than one image here. So for a step by step description of the bug go here: https://github.com/JoakimSoderberg/sketchup-svg-outline-plugin/issues/4
In summary, sketchup unzips in a subdirectory in the plugins folder like this:
If I move the files out of this directory it starts working.