1 If a change to a page is previewed, but not saved, `%pagestate` and
2 `%wikistate` can be changed, and saved. Actually, it's not limited to
3 those. Seems that spurious dependencies can be added, though existing
4 dependencies will at least not be removed.
6 It calls saveindex to record state about files created on disk for the
7 preview. Those files will expire later. However, saveindex also
8 saves other state changes.
10 Seems like it needs to isolate all state changes when previewing... ugh.