Feature summary (what you would like to be able to do and where):

When a chunked upload enters the publishing stage status infos can be polled from the API (upload stage). However it contains no progress information on the publishing success. The JSON returned should contain a progess information (either a percentage or a text string telling what part of the publishing has already been completed)

Use case(s) (list the steps that you performed to discover that problem, and describe the actual underlying problem which you want to solve. Do not describe only a solution):

A file of 4GiB can be uploaded in short time. Also the assembling of the file will take no more than half an hour. But the upload may stay in publishing stage for thee hours or more. If it ends with either "published successful" or "publishing failed" it is fine, but not so if it stays in publishing stage for hours. It is impossible to know if the publishing is stuck (forever?) or it there is still slow progress, that may finally result in a published file.

Benefits (why should this be implemented?):

It is more likely the files (especially large files) are uploaded to commons and not given up on.