Proposal 3 -- Q&A for enthusiasts and power users of Apple hardware and software
Edit the description on the list of sites so that it now reads Q&A for enthusiasts and power users of Apple hardware and software.
Now it is neither! As of June 13, 2016, the name has been changed to macOS https://www.apple.com/macos/sierra/
During the keynote at WWDC on June 13, 2016, Apple announced that OS X would be renamed macOS to stylistically match Apple's other operating systems, such as iOS, watchOS, and tvOS.
I've submitted a pull request to the GitHub repo. This pull request deals with resizing the ad to the necessary size and adding a border (required by guidelines).
Proposal 0 — It remains as it is.
Proposal 1 isn't suitable: the list of site descriptions are always of the form ‘Q&A for [scope]’.
Proposal 2 might be ok, but I don't think it's necessary. Many site descriptions use ‘power’ for the reasons discussed in:
Why “Pro” in “Pro Webmasters”.
As for me, (the newly added) proposal 3 sounds good.