Floor slab removed afterward, reinforcement visible

no, probably not. but if someone claims to have worked according to [DIN], they must have it and can prove the criticized point as flawless (by showing the exact spot in the [DIN]). with that, during the construction, I had everyone by the balls and they had to make corrections. because nobody had it ^^

if things get really tough, you can of course buy it or work at a company with a [DIN] flat rate. otherwise, for many well-known [DINs], there are also such explanatory stories, where excerpts from the original part are included as well.

Are DINs now freely accessible?

Yes, although not free of charge. However, one often finds a library nearby.

But it must be a very, very well-organized library Even our university library had perhaps 5.

No wonder the university library doesn’t have a printer. Employees of universities can very easily access any DIN standards online and download the respective PDF.

You underestimate the commercial aspect of the German Institute for Standardization... this is not an academic charity organization
But sure, with a little effort you can get them.