I reported https://bugs.launchpad.net/ubuntu/+source/grub2-signed/+bug/1800340 which (as so often) didn't get any feedback, so I reported it upstream at https://savannah.gnu.org/bugs/?func=detailitem&item_id=55005 and want to register the upstream issue in Launchpad. Unfortunately, the URL isn't recognized which seems to be an issue with different forms of URLs provided by GNU Savannah (details in the link) and furthermore a triaged bug in a contribution tool for 10 years.
Since in my experience (of reporting hundreds of bugs and spending hundreds of hours with similar problems and hearing of hundreds of people suffering from them) the change of getting these bugs fixed is zero, so I'd like to work around this one: Can I transform the upstream bug URL into one which is accepted by Launchpad? Does anyone has a list of URL forms for accepted GNU Savannah reports which can be collected here and linked in the report to allow others to work around the frustration this kind of issue handling causes for non-full-time Ubuntu contributors?
Never say never! A fix committed has been committed for the launchpad bug itself after two days and is now ready for QA testing. Awesome!
The fix is now released an I added the upstream bug reference to the GRUB issue (which hasn't seen input, yet).