Fixed a bug on how the browser wasn't closing TCP connections/Motion JPEG video streams properly in a responsive behavior. Took me about 3+ hours reading through various specs and that resulted to around 20 LOC changed. I then wrote a blog post about it[0], which took me about 10 days.
[0]: https://blog.whilenot.dev/posts/cool-bugs-vs-shitty-bugs-par...