all standard compliant desktop web browsers have built-in "developer tools". these are tools created for web developers, designed to help them debug && experiment w/how the code they've written (in HTML, CSS && JavaScript) for their websites && applications is running in any given browser. u can access these by pressing the F12 key (or Fn+F12 on Mac)
if u're a web developer u can learn all about how to properly use these developer tools on mdn (mozilla developer docs). this page, however, is all about how we can misuse these same tools to tactically undermine (remix, hack, jam) the code which the surveillance capitalist have written.
the browser dev tools have a few different tabs, below are links to pages documenting how to use some of these tabs:
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