Why F1 steering wheels have over 20 buttons – and what they all do | F1 technology
www.f1fanatic.co.uk/2011/04/22/steering-wheels
From the page
Saved with the link. Notes from 2007 to 2016 are mostly the page's own words, so this is probably an excerpt.
F1 steering wheels serve an obvious and important function. But F1 drivers use them to do much more than just point the car in the right direction.