Hi,
My backup history showed that I started out this morning with a TW filesize that had jumped up around 150K stayed like that for two revisions and then gone back down again - I couldn’t explain this jump in terms of my keyboard input, I don’t write that fast! so I looked into it fearing I had deleted something although I couldn’t explain the increase in the first place.
I did upgrade yesterday to 5.3.5 from 5.3.1 I used the online method dropping my local file to https://tiddlywiki.com/upgrade.html
Performing a linux diff on two files in my backup directory showed that the difference was the system import tiddler containing a list of all my tiddlers.
At a guess the upgrade process performed an import to the newer version TW but kept the list of my imported tiddlers in the import tiddler, at some point this morning a process or my activities triggered a clear up of the import tiddler and the space was reclaimed.
Just thought it worth a mention incase anyone else comes across this - once the reason is understood it’s not a concern.