@magnetik apologies that I didn't get a chance to look at this sooner.

It looks like the junit examples in the hook_failures_junit_(annotations|attributes).feature files need to be updated to add the new attribute there as well.

The implementation looks good to me - in a perfect world I'd rather have kept the code alongside writing the other attributes (e.g. in JunitScenarioPrinter) but from a quick look I think that would be challenging with the existing structure of the listener / printer / output classes. So I think you've found a good solution to add this to what we have already.

made me wonder if I should report the line only for failed steps because for valid steps, it will always return the last one

I think that's OK, it's probably better for end-users to consistently have the attribute present with "the line number of the step that ran" than to have to work out what it means / work around it only being present sometimes.

@magnetik thanks very much for updating this, there's one tiny change to pass the standards check - I'll commit that for you now (once this is merged, the CI will run immediately for any future contributions from you, so it'll be much easier to get feedback).

Thanks @magnetik