Help Identifying Leaky Line

Hello. I am new to these forums and a new owner of a 2010 Trail.

I'm hoping someone can help me identify an engine line that seems to be seeping/leaking. It's a beefy metal line that attaches to the ?valve cover? right behind the dipstick. (Image attached). Following the line down there is progressively worse oily buildup. All my search attempts have failed to identify what the line is so I'm hoping the knowledge base here will come through. An ideas on what may be the source of the leak would also be appreciated. The truck has a shop appointment booked in a couple of days and I'd like to go in with some (at least) basic understanding of what might be going on here
Looking forward to joining the discussion here going forward. Thanks.

 

VVT-i oil supply line.

 

Excellent. I appreciate the quick reply. I feel like I'm crazy but I just don't see this on any parts diagrams I can find. Hopefully this lead will help.
Hoping that it's just the line leaking and it's not the timing chain cover.

 

welcome

 

I had a very similar look with oil seepage on my 2014. Looked like it was leaking for a long time. Thought is was the oil supply line but turned out to be the timing chain inspection plate. Replaced the gasket with indian head gasket sealer and all is good now. The below video shows the location for the plate.

4.0L Toyota Oil Leak Square Plate Cover | Timing Chain Tensioner Cover Tacoma 4Runner Tundra 1GR-FE - YouTube

 

Noticed build up in same area of my 2018. In that video, he's already got other lines removed so that cover was easy access. Can you remove and reseal that plate without removing the metal lines in front of it (coolant lines?)?