To the best of my recollection no one in the former HN comment threads expanded on the long hiatus .. suggesting an absence of any real drama.
Which leaves us with the RC release candidate Announcement:
After a five year hiatus we're back with a GitHub organization, with new admins and new maintainers who have brought a great deal of energy to make a long-awaited and long-needed new release.
https://github.com/jqlang/jq/issues/2802and the 1.7 release Announcement:
It's been almost five years since the release of jq 1.6. Recently we have had a great influx of contributor and maintainer energy. We now have 12 maintainers (up from 3), with about 4 or 5 active maintainers (up from 0), we have 8 admins with several active admins, and several owners at least two of whom are active. As a result the project will not again have such a long hiatus.
https://github.com/jqlang/jq/issues/2876Either any dirty laundry is well buried or (more likely) this was simply a case of the original implementers hitting some plateau of achievement and fading away leaving JQ to eventually be picked up by others.
Others would have to chime in, I have nothing I can add.
