A car mechanic, generally speaking, knows that Snap-on brand tools are some of the best in the industry and that it takes a proper monkey not to be able to use one of the companys wrenches properly.
The problem with open source software application development (if there is one) you might argue is that there are so many comparatively ungraded tools out there that you can find yourself using a product that is not necessarily best suited to the job in hand.
Purists might argue that by its very nature, open source relies on community contribution and engagement and that a level of natural selection if you like arises from this.
In the survival of the fittest, only the most truly adaptable, fastest performing and most interoperable of anything will win. Whether it is Darwins finches on the Galapagos or open source driven GUI development framework toolsets, right?
With these thoughts in mind, I went looking for some discussion surrounding what types of tools are critical (or least most critical) to the success of software engineering with open source projects. Unsurprisingly, that is too broad a Google term to provide any sensible answer. But if you restrict your search to sub-sectors of the total software development process, then you can dig up a few morsels.