On Wikimedia wikis, local uploading should be disabled if there are no licenses set on MediaWiki:Licenses.
The need for this is because some or many small WMF wikis still do not have
license options, which is really needed for our copyright requirements.
https://wikimediafoundation.org/wiki/Resolution:Licensing_policy
This will be done in https://gerrit.wikimedia.org/r/#/c/136520/
After this change, simply putting any content on MediaWiki:Licenses will enable uploading again.
I developed a tool at https://tools.wmflabs.org/robin/?tool=uploadconfig which provides information about the status of each wiki.
Version: master
Severity: normal