Valve cover or rear main seal leak?

[COYS]

It’s leaking not at weep hole but the corner as you can see below.

I also noticed backside of engine with oil residue.

Is this a rear main seal job, valve or both? Many thanks.

 

[Tbkw01]

Open the inspection cover on the fed side of this area and look with a mirror. If the rear main seal is leaking you will see it by angling the mirror in this cavity.

 

[Tbkw01]

Correction-Forward in place of fed.