view source code and edit past revisions

Project:web site
Component:Code
Category:feature request
Priority:normal
Assigned:Unassigned
Status:active
Project wiki:How to use this web site
Description

We cannot view the source code and edit past revisions (e.g. to copy and paste a piece of code that had been deleted).

Create a module to do so.

Also, some past revisions will be official revisions of released videos (i.e. the revision will correspond to a specific version of a video).
What is the best way to tag them? How to prevent deletion of those revisions?