But at the same time, sometimes you have to really persevere to get a bug fixed.
Consider the perspective of the maintainer of a popular project: to them, you're one person in a big queue of people all reporting problems. Most issues turn out to be "I need free technical support, which you don't offer, so I'll phrase it in the form of a bug", and it saps their time to look into the details of each issue to find whether it's genuine-bug or user-error.
So that's why you should try to give reproduction instructions as best you can, and be up-front if they're incomplete, or you only saw it happen once.
If the maintainer responds harshly, or even if you get commentary from others, remember they are (or should be) criticising the bug report, not you. Try not to take it personally.
And even if they decide to close it, or not investigate further, you've still done the world a favour by adding genuine details about something you saw. The bug report is still searchable when closed. Other people who get the same problem as you are likely to find it, and it might spur them to reproducing the bug where you couldn't, and re-opening or re-reporting the bug and driving it forward to completion.
You're paying exactly $0 for support for this software. So any support (eg: bug fixes) you get are a gift. That means that if you (1) use their software, (2) don't provide a good bug reports to help them fix their bugs, and (3) complain about how it's not your job to fix them then... you, my dear person, are acting like an entitled ass.
It's not hand-holding to provide a good bug report, it's essential to make the bug report actionable. curl is so widely-used that bugs often come from a combination of the software and the environment (OS, libraries, etc). Without enough details to reproduce a bug, then the bug is often impossible to track down. This means: recreate the environment, the actions that led to the bug, and create the bug itself.
But at the same time, sometimes you have to really persevere to get a bug fixed.
Consider the perspective of the maintainer of a popular project: to them, you're one person in a big queue of people all reporting problems. Most issues turn out to be "I need free technical support, which you don't offer, so I'll phrase it in the form of a bug", and it saps their time to look into the details of each issue to find whether it's genuine-bug or user-error.
So that's why you should try to give reproduction instructions as best you can, and be up-front if they're incomplete, or you only saw it happen once.
If the maintainer responds harshly, or even if you get commentary from others, remember they are (or should be) criticising the bug report, not you. Try not to take it personally.
And even if they decide to close it, or not investigate further, you've still done the world a favour by adding genuine details about something you saw. The bug report is still searchable when closed. Other people who get the same problem as you are likely to find it, and it might spur them to reproducing the bug where you couldn't, and re-opening or re-reporting the bug and driving it forward to completion.