Currently there's no good way to provide the source files for a complex media item that can't be directly edited on-wiki:
* GIF animations created from .... some sort of source
* SVG images that use data or text from other SVG or raster images
* TIFF/PNG/JPEG/etc that's cropped or filtered from another source file
* audio/video clips trimmed from another clip or composited from multiple source clips
And of course our favorite bugaboo:
* audio/video clips with source media in non-free formats
* GIF animations with source media in non-free formats
* raster images with source media in non-free formats
* etc
The result of discouraging provision of non-free source data is that many of our diagrams and animations are provided not in an editable format, but as flattened final PNGs/GIFs/movies with *no source files at all*... so they cannot be edited or modified other than by slapping additional text or graphics on top of the flat version.
We need to seriously think about how to create spaces for source files:
* do files in "funny formats" need to sit somewhere else? (eg another site, like the experimental schnittserver or various tool-labs thingies?)
* or just a separate sub-place on Commons from the direct-inline-usage File: space?
* how much connection do those source files need to their derivatives? should they be reusable in multiple File:s or linked inextricably to a version of a particular File:?
* do we need to limit to free formats? do we need to provide server-side conversion tools?
* what kind of in-browser and in-app editing tools can we provide?
* do we need more good tools to replace popular non-free tools like Photoshop (multi-layer raster editing), Matlab (lots of graphs and diagrams), chart drawing, etc?