This scope lets an app "Add, edit, and delete files and file comments"
This feature was exclusive to our workspace apps developer preview. The preview has now ended, but fan-favorite features such as token rotation and the Conversations API will become available to classic Slack apps over the coming months.
files:write only works with workspace apps.
Originally, workspace apps needed file:write:user. Learn more.
This OAuth permission scope works with these Web API methods.
files.comments.delete - Deletes an existing comment on a file.files.delete - Deletes a file.files.revokePublicURL - Revokes public/external sharing access for a filefiles.sharedPublicURL - Enables a file for public/external sharing.files.upload - Uploads or creates a file.