The Tor Browser / file revision

 function a(){b()}function b(){debugger}

 //# sourceMappingURL=data:application/json;base64,eyJ2ZXJzaW9uIjozLCJmaWxlIjoiYWJjLmpzIiwic291cmNlcyI6WyJkYXRhOnRleHQvamF2YXNjcmlwdCxmdW5jdGlvbiBhKCl7YigpfSIsImRhdGE6dGV4dC9qYXZhc2NyaXB0LGZ1bmN0aW9uIGIoKXtkZWJ1Z2dlcn0iXSwibmFtZXMiOltdLCJtYXBwaW5ncyI6IkFBQUEsaUJDQUEsQ0FBQyxDQUFDLENBQUMsQ0FBQyxDQUFDLENBQUMsQ0FBQyxDQUFDLENBQUMsQ0FBQyxDQUFDLENBQUMsQ0FBQyxDQUFDLENBQUMsQ0FBQyxDQUFDLENBQUMsQ0FBQyxDQUFDLENBQUMifQ==

 // Generate this file by evaluating the following in a browser-environment

 // scratchpad:

 //

 //    Components.utils.import('resource://gre/modules/devtools/SourceMap.jsm');

 //

 //    let dataUrl = s => "data:text/javascript," + s;

 //

 //    let A = "function a(){b()}";

 //    let A_URL = dataUrl(A);

 //    let B = "function b(){debugger}";

 //    let B_URL = dataUrl(B);

 //

 //    let result = (new SourceNode(null, null, null, [

 //      new SourceNode(1, 0, A_URL, A),

 //      B.split("").map((ch, i) => new SourceNode(1, i, B_URL, ch))

 //    ])).toStringWithSourceMap({

 //      file: "abc.js"

 //    });

 //

 //    result.code + "\n//# " + "sourceMappingURL=data:application/json;base64," + btoa(JSON.stringify(result.map));