IMO this is an improvement that provides a little more guidance without becoming a full-blown gdb tutorial. There is a missing space that needs to be fixed and some structural issues (i.e. perhaps moving some text around) that can be discussed, but I'm +1 on the changes in principle.

A couple more minor changes, but otherwise I think this looks good.

After a more careful look at the diff, it seems that some of the original meaning has been altered a bit in the reorganization of the wording. I think it would be best to try to recapture the original meaning that the user should make sure gdb is installed, and if the Python extensions are also installed then additional Python-specific commands are available.

I still don't think we're quite nailing the wording - I hope I'm not being too obstinate. I've added a wording suggestion that tries to capture my comments.

IMO the big improvement here is related to the examples you've added.

LGTM - thanks @Qiyu8 for your suggestions in improving the debugging docs! IMO the additions are nice as they help give the user a little more guidance in verifying they have the debugger set up properly for this procedure. I also think the listing of gdb commands is an improvement, even though it's not NumPy/Python specific. We'll see what other reviewers think!

This definitely looks more useful. LGTM!