Extra plug on Plus PSU

Just a quick question.
Just put together my SV06 Plus, so far so good. Must say this sucker is hugh.
I;m used to my Ender Pros. There tiny compared to this beast:)

Quick question
Whats the extra pluf for on the PSU?
Not the run out sensor plug, but the extra one?

Ignore this post…
I just looked closer, it just where the run out sensor plugs into the Main Board (my bad)