Why am I getting "Invalid object name 'sys.sysobjvalues'." When I run 

SELECT OBJECT_DEFINITION(OBJECT_ID('sys.assembly_files'));


I can see that there is a self-join on sys.sysobjvalues, but when I try to select that table I get,

Msg 208, Level 16, State 1, Line 1
Invalid object name 'sys.sysobjvalues'.


What's going on here? Why is that object name invalid?
This is one of the tables that can only be accessed over DAC, from this blog


  They had been moved to the imageval column of sys.sysobjvalues, which can only be accessed when using the Dedicated Admin Connection (DAC).


Prolly not a good idea, but for proof it'll work connect to DAC (-S admin:localhost on Linux)

sqlcmd -S admin:localhost -U sa -q "SELECT * FROM sys.sysobjvalues;" | less -S