It's a rather poor-quality image, but what it shows is a corner where two wall sections meet. In the middle of the corner, an old paper-insulated GEBE/EDIL cable is screwed up, but the gray part visible to the left of the clip under the wallpaper is a thin shiny metal plate nailed vertically to one wall. The plate is about 92 cm long and maybe 6 cm wide. The wall it is attached to (the one to the right of the cable) is studded (while the wall to the left of the cable is bricked). Where the plate ends at the bottom, a masonite wainscoting begins, and the plate doesn't quite reach all the way up to the ceiling.
What is the purpose of the plate? It is in the bottom layer of original paint, so it has apparently been there since the house was built in the late '20s - the cable was probably added a bit later even though it is also old now.
There are no signs of a plate on the left bricked and plastered wall.
It is not entirely uncommon for there to be a hole behind where the mice have entered through. I have torn apart 2 houses now where various sheet metal bits were used to cover the mice's entry points into the house.
Seems older than the street, is it the basement, are there any screws, nails or anything else holding it, could it be something to hold the corner together, reinforcement so it doesn't come apart there, otherwise I don't know.
Not entirely uncommon for there to be a hole behind where the mice have come in, have torn into 2 houses now where various metal pieces have been used to cover the mice's entrances into the house
However, this is not a patch but something that was put there from the beginning because it is painted over with the same color that is the bottom layer on the entire wall.
Seems older than the street, is it the basement, are there any screws, nails, or other things holding it, could it be something to keep the corner together, reinforcement so it doesn't come apart there, otherwise I don't know
It is the hallway and it is attached with heavy nails straight through.
Yes, I am also considering corner reinforcement but don't see any metal on the other wall. But maybe it's under the plaster on the other wall? The cable is a bit in the way but I'll see if I can dig a little...
It is not a lying log in the old wall and it is supposed to function as a dowel and hold these together in some way, so they do not separate
Good thinking and it would have been reasonable since it's the heart wall - but the sheet is nailed on top of the wall paper and doesn't go all the way down either, so it doesn't feel like it helps structurally. Could it have been protection for some cable? As mentioned, the cable in the picture should be newer, and for the telephone cable that was just there, it seems unnecessary.