Steps to Reproduce:
query the parameter info on sandbox for the upload module via
the JSON result shows the "required" field is only shown for "token" and its value is "" empty.
According to recent discussion I had on IRC for wikimedia-commons, at a minimum it seems "filename" should also have a "required": true along with "token" ?
But there might be other fields that should have "required" set to true, I am unsure.
Generated docs I referred to are https://commons.wikimedia.org/w/api.php?action=help&modules=upload
In fact, I'm not sure if other APIs and modules are correctly setting their "required" field for parameters. This probably needs more thorough review at higher task level for some maintenance work by the API teams, so please tag this bug accordingly to sub-tasks or epics as necessary.