GrowthExperiments uses community configuration for rendering special welcome pages (see T307521: Support templating for Growth campaign landing pages), which includes specifying some file names to display those files from Commons (or the local wiki if it exists there), e.g. the video in T303771: [Epic] Account creation: social media marketing. It would be nice to avoid accidental modification of these files. One way to help that would be to integrate campaigns with file usage so there is some indication at the "File usage <on this wiki>" / "File usage on other wikis" section of file pages that the file is being used for a campaign.

Maybe we could create a special page like Special:GrowthCampaigns, have it say something along the lines of "these files are used for campaigns, please be careful changing them" (and potentially other more useful things about campaigns), and then insert it into the fileusage and globalusage tables for the given files. Or maybe use the campaigns' JSON configuration page instead, if usage tracking requires a real page (that seems more straighforward, just need to customize the parsing of that page, though also more disorienting for people clicking through from the file page).

In theory that could even be used for some sort of cascading semiprotection, although cascading doesn't work across wikis so the usefulness of that would be very limited.