The only time I'd want to be able to look at the source code of a third party component and modify it is when that component is FOSS. That's because I often come across strange hard coded configurations that make sense in some version-last environment but don't make sense given currently updated components. It seems that FOSS developers tend to assume that other devs will inevitably look at the source, so it doesn't matter. This isn't necessarily a bad thing because there are people who enjoy hunting through foreign code to patch things up. Unfortunately, I'm not one of them.