We use to stick into the SubtitleVersion.note strings such as "Rollback from version#" or "Uploaded" automatically. This was handy, because when looking at the review list, you could see that info. Helps debugging but also teams / users to grok what's going on.
However, it does have it's problems: no i18n / hard to customize messages, etc. For rollbacks,it's easy: since we already store the rollback_from_version_number, we can just check that and display that info.
I see the following alternatives: a) Stick it back into the SubtitleVersion.note field, with the issues raised above
b) Create a boolean ("from_upload") Keeps notes clean, easily 18n and customizable. However... (see bellow)