Ruby: What does 'require: false' in Gemfile mean?

Does this:

gem 'whenever', require: false

mean that the gem needs to be installed, or does it mean it is not required?

This means install the gem, but do not call require when you start Bundler. So you will need to manually call

require "whenever"

if you want to use the library.

If you were to do

gem "whenever", require: "whereever"

then bundler would download the gem named whenever, but would call

require "whereever"

This is often used if the name of library to require is different than the name of the gem.

Stack Overflow Q#4800721, score: 531