What are admin navigation link IDs/section IDs/tab IDs?

[Luxus]

I have found these error messages in XenForo's phrases:

Please enter a valid admin navigation link ID.
Please enter a valid admin navigation section ID.
Please enter a valid admin navigation tab ID.

However there are no link IDs, section IDs and tab IDs for the admin navigation in the ACP. There is only a normal admin navigation ID, whose error message is used in library/XenForo/DataWriter/AdminNavigation.php.

So what's the reason for putting those messages in xenforo when they are not used at all?

 

[Mike]

They were historically used.

 

[Luxus]

They were historically used.

Oh I see. I have found a bunch of other phrases that seemed not to be used anymore. Is there any reason to not remove them? Because those would confuse translators looking for context.