I’m very happy about the new(ish) email mark in writer fields (Missing email-mark in the new writer field · Kirby Feedback) but alas email addresses are output without any obfuscation. Am I missing something or would this require a custom filter?
Where are you looking? If it has been obfusificated, youll be able to see it by doing View Source. If you look at the code via the browser console, most browsers are clever enough to convert it back inside the console, so it wont look obfusificated there, but it actually is obfusificated in the raw HTML 
It would require a custom filter.
yes, I checked the raw source code, of course… 