It seems equivalent to desktop for me. Add-ons -> [add-on-name]: opens the modal content for an addon Add-ons -> Add-ons manager -> [add-on name] -> Settings:

It seems equivalent to desktop for me. Add-ons -> [add-on-name]: opens the modal content for an addon Add-ons -> Add-ons manager -> [add-on name] -> Settings: opens the settings page for an addon in a new tab.