As a hobbyist dev you don't need an imprint - unless you're selling software, at which point you're a business and your customers should be able to hold you accountable for it.

You need an imprint for pretty much everything, as I wrote earlier. Even a hobbyist Youtube channel requires one if you're strict with it. It's enough that said thing could have business intent and I want to emphasize the could here. To be completely sure, you'd have to check with a lawyer.