Not much 'euro', eastern europe is missing as a whole. E.g. polish Ł, czech ř, slovak ô, ... Either use dead keys for all diacritics or somehow add them all to the third and forth layer.
Wouldn't this solve much of the problems of these keyboard layouts by reusing the same letters?
But I'm talking about the euro-layout, there are keys for ý, ä, ü, ö, é, .... All of these are 'western' special characters, no eastern europe (slavic language letters) or greek letters. So users of _these_ languages, need to use dead keys or some other method (I don't know to get greek letters with this layout) for at least some of their 'special' glyphs that are not, by chance, also used in another language (for slovak and czech that's for example ä, ú, á, é, ý and í).
Highly recommended. No idea though for any other languages other than German.
> It's preinstalled on Linux
Note that at least on Ubuntu/Debian, the included version is older and a bit different. Not unusable or anything, but not the same as on the website.
It's preinstalled on Linux, and available for macOS and Windows as well. I feel a keyboard based on the US layout which far too often is considered a standard (better for coding and buggy software and games), with dead keys and diacritics is a fantastic idea.
I have migrated all my machines to use it instead of the custom layouts or the US one that's very restrictive when you need to write accents.