I do not see
anything from Liberty that says they have a back door. They do keep a record of the combination the safe is shipped with, should the owner forget, but you can change the combination on a safe in about 5 minutes and the manufacturer would have no way of knowing what it was changed to.
On good safes (ones with dial locks instead of keys), regardless of whether they are electronic or manual dial, the lock mechanism itself is mechanical and as far as I know, is only capable of supporting one combination at a time, so there is no way the manufacturer could have a 'secret' code to open a safe. Of course that won't stop some journalist from misstating the facts.
Here is a more comprehensive article on the story:
Gun Safe Manufacturer 'Liberty Safe' Gives FBI Access Code to a Protestor's Safe Who Was Arrested at Gunpoint Due to Involvement in January 6th Capitol Event (VIDEO) | The Gateway Pundit | by Jim Hᴏft
Much ado about nothing....