Some interesting history of source maps: They actually are older than the article suggests, having been original developed and used internally at Google starting in early 2009. At the time, Google had some of the largest applications written in JavaScript running inside of the browser, optimized and minified using Closure Compiler [1]. One focus of Closure Compiler was/is minimizing bytes sent over wire, which resulted in trying to debug issues that occurred on Line 1, Character XXXXX of the minified file. As an engineer working 20% on a Gmail feature, I grew incredibly frustrated with having to add `console.log` or `alert` calls everywhere, and so threw together extensions to both Closure Compiler and Firebug to produce the very first iteration of source maps. While only used by a few members of the Gmail and apps teams at first, the source maps and “LavaBug” (our extension to Firebug to consume source maps) spread internally, so much so that we decided to release them as part of Closure Compiler’s first release (“LavaBug” being released as “Closure Inspector”) [2].

The reason the spec lives in a Google Doc is that it is not a standard; it is a specification that we wrote at Google and saw teams both internally and externally pick up as it gained steam, eventually being supported in all major browsers and most compile-to-JavaScript tools; shows how having a solution to a problem can cause it to grow into a “standard”.

Source: I invented Source Maps

[1] https://github.com/google/closure-compiler [2] https://googlecode.blogspot.com/2009/11/introducing-closure-...