Allow add-on installs from websites
Supported on: Firefox 60 or later, Firefox 60 ESR or later
Registry
HKLM
Software\Policies\Mozilla\Firefox\InstallAddonsPermission HKCU
Software\Policies\Mozilla\Firefox\InstallAddonsPermission Value name: Default
Enabled: Default = 1
Disabled: Default = 0
Description
If this policy is disabled, add-ons cannot be installed. If this policy is not configured or enabled, add-ons can be installed.