Frequently Asked Question
Yes this is just created when disabled Fx are updated automatically. It is kept for backup purpose but you can safely delete those if everything is working fine.
The Update folder is in your user Motion Template library :
To open the Update folder, go to the Tools menu and select "Open updates"
All the plugins in this folder are old versions that were in Disabled and that FCPX Manager replaced by a new version that was installed in the regular Enabled folder. After moving the old Disabled version to the folder call "Updated", FCPX Manager moved back the new version to the Disabled folder to maintain it in the Disable state as it was before. So anything in the "Updated" folder is old data that you can remove.