Linuxisms in s6

[Jonathan de Boyne Pollard]

http://adrianchadd.blogspot.co.uk/2016/08/freebsd-on-tiny-system-whats-missing.html?showComment=1471236502051#c1305086913155850955 
, Adrian Chadd:

> We're using s6 at work, and it works out mostly ok. Mostly once you 
> get around the linuxisms, and the lack of sensible time code in it 
> (its calculations for daemon run duration is based on system time, not 
> wall clock, so if your box boots jan 1, 1970 then gets NTP, things 
> are.. hilarious), and some of the arcane bits to get logging working 
> right.
>
What are these Linuxisms in s6?  s6-linux-utils and s6-linux-init have 
Linuxisms, obviously.  But what Linuxisms does s6 have?