Richard Cook explained the Above the Line / Below the Line Framework in about 5 min at Velocity NYC 2017. Once you adopt this Perspective, once you step away from the idea that below the line is the thing you're dealing with and understand that you're really working above the line all sorts of things change. youtube 
report
https://www.youtube-nocookie.com/embed/6jYoACO7qzg?start=95&end=333
HEIGHT 285
David Woods & Richard Cook. Stella Report. Velocity NYC 2017. 1m35s—5m33s
youtube report
See another telling by John Allspaw from DevOps Enterprise Summit 2017. Human Performance in Systems
a typical view of the software system serving customers
a view of the system which includes the deploy tools, version control, testing, monitoring
The part of the system most software people miss. This Drs Woods and Cook showing all us fish what water is.
This is the inclusive view of the system divided by the line of representation. Humans above, computers below.