It looks like its currently broken, based on https://github.com/geoserver/geoserver/commit/c4967ff152e4bff8996391ec76be8c91527859ba
You can try to fix it if you like.
I’ll prepare a pull request to disable it from being included in the docs.
From: Nanaso via Geoserver-users <[hidden email]> Sent: Sunday, 30 September 2018 12:23 AMTo: [hidden email]Subject: [Geoserver-users] Can't find "Resumable REST Upload Plugin"
Hi Geoserver's users,
I have found this page in the docs that speaks about "Resumable REST Upload Plugin":
However, I can't find the plugin's zip file to download. It's not there in the link given in the doc link.
Where can I find this file?