Fabia leccy sunroof glass edge rubber/seal

This seal on the edge of the glass seems quite firm/dry and prone to green stuff (algae/moss?) growing on it. I'm not sure if that is the weather seal itself or not but was wondering if there were any good products out there to clean it with/maybe keep it from drying out and cracking etc?

I'm using white lithium grease on the sunroof rails to lubricate those.

Thanks in advance.