I’m glad it was of use to you.
Yeah, uninstalling software is a bit tricky in Linux. They have come a long way in making software easy to install, but they still have a long way to go to make it easy to uninstall.
It is ironic but one of the common complaints about Windows is that the OS slowly gets bloated with unneeded files – but exactly the same thing happens in Linux. In fact, I would say the problem is worse under Linux.
Thanks for your comment.

Thank you very much for your positive comment!
Yes, I do put a lot of time into each article – sometimes I wonder if all the effort is worth it, but each positive comment tells me that it is.

Thanks for the comment.
In addition to the history.log file, you may also have several history.log.<number>.gz files. Periodically, aptitude will start a new history.log file and gzip the old one. I am not sure what triggers this, but I think it is a software update.
If you can’t find what you are looking for in the history.log file, then it might be in one of the gzipped files.
Yes, Libre Writer does work with regex, unfortunately, it has changed the regex behaviour between version 3.4 and 3.5 (mind you, my original regex expression was probably buggy and Libre Office has just tightened up the regex handling).