Spanish.

The handrail is made of welded metal and connects only to the stairs, which are floating, so the fastening to the wall is preventing the rail from wobbling. Perhaps something could bend badly if a lot of sideways force were applied and the fastening to the wall is nonexistent, but at least among fit adults you would need a quite reckless behaviour for this, since once one notices it's loose, one can just stop using it when walking up the stairs (it just takes a bit more load on the legs when doing it so many times a day). But it's never gonna fall or anything like that, since the other points are very firmly attached to the metal frame that holds the floating stairs. So the setting in the image is not possible, but I have considered attaching a vertical wooden panel to the wall to grab from different points to the wall, and then the end of the rail to that.

But for the moment I managed to make it quite secure with that metal dowel I mentioned in the last post. If it gets loose again I may consider the plank, or making a hole at the other side.

As for whether the metal behind is just a stud for the plasterboard or something stronger, I don't know. It's a 250-year-old-house renovated 40 years ago, and has a combination of old wooden and newer metal structure inside. Could be a bit more structural than just the metal studs used to hold the plasterboard in place, especially since it's a corner of sorts, but it's very difficult to know.