...
This works for the following plugins:
Caribou (Elk)
Crane
Human
Lumion Livesync
Lunchbox
Ngon
PanelingTools
Parakeet
SectionTools
treeFrog
Weaverbird
It does not work for these plugins (see this page for how to install many of them):
Hoopsnake
Ladybug + Honeybee
Octopus
ParakeetRabbit
Using Package Manager
Start Rhino 8 and enter packagemanager on the command line.
In the Package Manager search box, search for a plugin, such as Weaverbird.
...
Click Install and then OK.
Restart Rhino before using the plugin.
Most plugins will appear on the Rhino or Grasshopper menu.
Common Issues
If you don't see a plugin available in Package Manager, we may already have installed it using alternate methods. Check the menus under Grasshopper.
The Package Manager does not exist for Rhino 6.