iOS is lowercase for two reasons:

• Naming consistency. Since they are already name it iPhone, might as well name the OS the same way.
• The name was already in use. This may have not been as significant for choosing the name of Apple’s OS, but when the first iPhone released, Cisco IOS was already a family of operating systems for routers and network switches, and the Wii had already released a few months before, and they also called the console’s operating system(s) as IOS.

Here is a decent starting point in answering your question (the article has a few examples that are mostly related to open Internet protocols): https://en.m.wikipedia.org/wiki/Embrace,_extend,_and_extinguish

Hey OP, do you mind checking if your book explains the type coercions that are used with the + operator? I remember it also being mind-boggling, so I was hoping you book could demystify it too.

You’re right, the license is Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 (weird choice for a code license, but OK)