'before_widget' => '<li id="%1$s" class="widget %2$s">',

what is the id="%1$s" and sophisticationEqualsInchgolf widget %2$s" meaning?

As a result it does not mean much.

But I am speculating this really is used later having a function for example [cde] -- by which situation, individuals sprintf() and %1$s are markers that indicate where strings is going to be injected into that certain.

Begin to see the good examples about Argument changing around the %2$s manual page -)

I'd reckon that individuals sprintf()s are changed afterwards with actual values they are placeholders. Here's what i'm saying (in Python):

%1

The print 'One {0} three'.format('two') (inside your situation {0}) is changed with %1.