[scottyb]

What is a redundant diode.
Or a redundant anything for that matter?
So, I googled it.

re·dun·dant
rəˈdəndənt/Submit
adjective

not or no longer needed or useful; superfluous.

synonyms: unnecessary, not required, inessential, unessential, needless, unneeded, uncalled for;
More
(of words or data) able to be omitted without loss of meaning or function.

ENGINEERING
(of a component) not strictly necessary to functioning but included in case of failure in another component.