I will talk about accepting outside contributions in a general sense (beyond JS and Julia comparisons).<p>In my personal experience, the acceptance rates doesn't really matter and does not correlate to the quality of the code. On one hand, you have SQLite which really <i>discourages</i> direct code submissions due to the nature of the IP management of SQLite (they need to ensure that it is 100% in public domain), instead relying on bug reports instead. SQLite however <i>is a very good product</i>, something that I personally miss when I work on JS projects.<p>On the other hand, I've seen projects (multiple, which I prefer not naming to prevent flame wars) with very high acceptance rates - the problem is that the coding style and availability of comments are inconsistent to the point that we have to forego using some libraries and writing our own despite those libraries will fit into the bill nicely.<p>Edit: some have commented "this is what I've expected!", but there are some projects (obviously will be unnamed) that are not accepting contributions but the code consistency is less-than-ideal, and some projects with well-behaved outside contributors that have kept the quality despite having high acceptance rates (usually writing in relatively niche languages). Probably the area I'm working on (educational) isn't reflective on the wider community, which seems to associate higher rejection rates to quality.