ᐅ Shed Roof Without Eaves – Questions

Hello everyone,
Our house has a shed roof without eaves.
I have uploaded a picture and have a few questions that I hope someone can answer.
1) What is the name of the metal cover that has holes on the underside, and what is its purpose?
2) This metal cover as a whole is uneven in some places compared to the plaster or the wall (hopefully visible in the picture?). Is this correct? If not, is this a defect for the builder, and most importantly, what issues could arise?
Thanks in advance.

That is called a parapet.

And what you refer to as unevenness is likely within the acceptable range and purely cosmetic.

I would still raise it as a concern.

Thank you.
Is this also called the parapet on a roof? I only knew it from roof terraces.
Here is another picture of the roof...
And what would be the purpose of these holes (visible in the first picture)? Thanks

Depending on the roof construction, roofs are often ventilated behind the cladding to prevent moisture buildup— for example, with double standing seam zinc coverings beneath the waterproof layer— because condensation can form under the metal sheets. If this moisture is not drained away, the supporting structure will eventually rot.

This ventilation layer needs openings at the edges to allow air and moisture exchange. The area is covered with perforated metal sheets to prevent animals from easily nesting in the ventilation space.

A look at the roof construction plans should provide information about the executed roof buildup.