Thanks for spotting this. The setting isn’t showing up because it’s supposed to be added to the Uploads section of the media page, which doesn’t exist for sites on multi-site.
Even if we move it to the default section, the limit set on a particular site will be applied to all other sites on the network.
I think the best solution would be to instead add the setting to the network’s global Settings page, and the limit would then be set by the Super Admin and applied to all sites. I think something like this makes more sense as a network-wide setting anyway. What do you think?
