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?