Spaces, new lines, tabs, semicolons

Tip: Recall "Immediately-Invoked Function Expression (IIFE)" and "five problematic characters" JavaScript concept.

Answer: Name of the practice is " defensive semicolon". It allows you to safely concatenate several JS files into one, to serve it quicker as one HTTP request.
consider this resuls of concatination:

(function(){...})()(function(){...})()

Read it for details:
A lot of details: Immediately-Invoked Function Expression (IIFE)
wikipedia.org: Immediately-invoked function expression
pdf document: ECMAScript® 2015 Language Specification