What's this electrical connector for?

[en2rafg]

Hi all,

While taking the interior of the van out, I came across the electrical conenctor highlighted. It's on the RHS of the van inside the top cupboard. Is this a connector for fitting rear speakers, or a third brake light, or somthing different altogether?

Thanks!

 

[Louis II]

T5 has a wire that comes through there for speakers in the cupboard. Not sure about the T4.