Snapshot Editor

I would like the ability to add deduceable information to my snapshots manually, since the system doesn't add them automatically.
Let's say blue has 4 terts, and I know from ancient data what all 4 are even though I can only see 3. When yellow takes one, I now know that yellow has that territory, and I want to be able to mark that information into snapshots. We could add a symbol like X to represent unknown troop numbers and an inverted question mark to mean that we only have an educated guess that it is where they are.
Let's say blue has 4 terts, and I know from ancient data what all 4 are even though I can only see 3. When yellow takes one, I now know that yellow has that territory, and I want to be able to mark that information into snapshots. We could add a symbol like X to represent unknown troop numbers and an inverted question mark to mean that we only have an educated guess that it is where they are.