I have a Jira Software Cloud site that's around 10 years old.
I've recently been doing housekeeping and trashing > permanently deleting historical Jira Projects.
In the Create Issue screen, I include the "Sprint" field to easily add a candidate item into a Future Sprint (or the current Active Sprint).
I noticed the "Only show sprints in this project" checkbox: out of curiosity, I unchecked it and I noticed _loads_ of sprints from the historical, and now permanently deleted, Jira Projects.
I believed this was because the Sprint might have existed in existing issues but JQL 'sprint = "[an example sprint that is no longer in use]"' returns 'no issues found', so that's not it.
I then checked "Boards > View All Boards" in case the data is in an historical board, but only boards in my current projects are there, so that's not it either.
Does anyone know where these historical sprints are coming from, and moreover how to purge these historical sprints from Jira Software Cloud so they don't clutter my "Sprint" field drop-down in the Create Issues screen?