The Extension:MultiUpload page says that you've taken over maintenance of that extension from Tderouin, who has abandoned it. I'm very unclear how this process works, and I'm confused. I applied a while back to maintain this extension, and successfully had a git repo created for that, so I thought I was the maintainer, though I haven't made time to work on it yet.
My intention was to check in a completely new piece of code in place of the existing extension, since I've written a new MultiUpload interface as part of a different project. Here's a demo video: https://www.youtube.com/watch?v=4d90Tt5EGAc
Do you want to do something different with MultiUpload? Would it be better for me to create a new, separate extension and leave MultiUpload to you?