HN does this with some words, mostly ones that would typically be used in a clickbaity way, I believe.
I just tried posting "10 ways to test if this title works on HN" (the number thing being one I recall encountering before). The title was automatically changed to "How to test if this title works on HN". So there is definitely support for automatically editing some common clickbait title phrases.
It seems to be regex, I tried again with "12 ways to test if HN automatically formats titles" and it was also changed to "How to test ...".
If it breaks your title, you can fix it manually! You should see an `edit` under the title that will link to you an editing page that allows you to edit the title. This works with both link posts and text posts. I was able to change the title of my test post back to "10 ways to test ..." and it correctly updated to show that title with no modifications.
And I just now realized that this is actually one of the probably few things not mentioned on that one repo [1] that documents undocumented HN features!
[1] https://github.com/minimaxir/hacker-news-undocumented
