Thanks for your input.
Could we hide the download button? Sure. Does it mean people can’t download the PDF? Of course not, they can simply grab the ‘magic’ url used by our PDF viewer or use 100 other tricks to get it.
So the reason we don’t currently offer DRM-ish features like “can’t copy” and “can’t print” and “can’t download” is because they are just creating a false sense of security. There is no technical way to offer ppl to VIEW something without letting them download it in the digital world - see how often the security of things like Netflix and others is broken. This is a hugely complicated thing to do, requiring super invasive technologies like special encryption chips and limits on what devices and operating systems can be used (certainly not open source tech!) and legal threats and pervasive surveillance and spying and at the end of it all, it STILL gets circumvented.
You realize all this, indeed. And yeah, a cleaner UI is useful for your specific use case. But I would think it is niche enough that this would be something to offer with a Nextcloud app - something that would be quite easy to write, actually. It is certainly not a feature common enough to clutter the default UI with, imho. Especially due to the ‘false sense of security’ issue that will certainly create a difficult conversation with our security team - they will certainly not like this at all, calling it fake security and all that.