==What to do
Currently, users can enter Commons categories into the Category filter during setup. The filter, however, applies only to //pages// and has no effect on uploaded files. We will change that so on Commons, Category filtering applies to files (and not to pages). Once this functional change is made, add a line of text to the Category filter UI to explain the feature to users.
==Why are we doing this?
Commons editors are interested in tracking their uploaded files. The Category filter is a useful tool for focusing metrics, but it's useless on Commons because it works only with pages—which are of little interest to Commons users. So on Commons only, we'll make it so that Category filtering works with files.
==Requirements for Category filtering on Commons
- On Commons (only), category filtering will apply only to files, not to pages.
- [As far as I know, page metrics already don't get counted on Commons: e.g., we don't include Commons in Pages Created, Pages Improved, Edits, Bytes changed, etc.] !!@MusikAnimal, please confirm.!!
- Conversely, on other wikis, categories will continue to restrict metrics only for Main namespace pages. Category filtering has no effect on files uploaded to Wikipedias. Which means that all "Files Uploaded" to local wikis will continue to be counted, no matter what categories they are or are not in.
- As now, Commons Category filtering will be available only for Events for which Commons was specified as a wiki of interest during setup.
==Change to Category filter UI
Add the following line of explanatory text to the filtering UI, positioned and styled as shown in the screenshot below (This layout assumes the changes in T209107 are already complete)
- On Commons only, use this to filter files (images, videos, etc.), instead of pages.
==Metrics this will impact
Any metric related to files uploaded. E.g, from the Event Summary report (T205561):
- Files Uploaded
- Pages with uploaded files
- Uploaded files in use
- Avg. daily views to files uploaded
- (This will also, obviously, impact all metrics in the Files Uploaded report, which hasn't been specified yet.)