https://docs.google.com/document/d/1SZx ... sp=sharing
The Add-on File Registration System is intended to create an add-on file repository that all add-on developers need to submit their files to.
...
On the client side, Firefox will compute the hashes of add-on files being installed and query the API for it.
If the file is registered, it can be installed, otherwise it can't (there is planned transition period to ease adoption).
There will also be periodic checks of installed add-ons to make sure they are registered.
Ugh.
EDIT:
Just saw that there's already a thread: viewtopic.php?f=19&t=2764115
.