This third-party developer extension is locked, preventing it from being disabled or enabled. This is usually reserved for core extensions which must always be enabled, e.g. the user manager (com_users).
As discussed elsewhere, locked extensions cannot be enabled or disabled. While there are some legitimate reasons for third party extensions to do that (e.g. installer plugins which would prevent the extension from being updated when disabled, or security extensions requiring their system plugins to be always enabled to provide protection to your site), it is very uncommon.
There are two problems with a locked extension.
When the extension is disabled you cannot enable it. This is a problem with modules and components which will display nothing or an error respectively when they are disabled.
When the extension is enabled you cannot enable it. This becomes problematic if you have a third party plugin which you suspect somehow breaks your site. You cannot even check whether disabling the plugin would fix your issue, thus proving your suspicions.
Onthos lets you Unlock the extension.
Fun fact! The existence of third party, locked extensions which were impossible to fix without some dangerous database surgery was one of the reasons we decided to create Onthos.