I have a text file (a log) sized 110 MiB with 530k lines. I do Ungrep with an expression that eliminates around 510k lines. In the latest build this takes up 27 seconds. In one of the oldest builds (2015) where Ungrep was first implemented this takes up 15 seconds.

Question: you were supposed to optimize grep/ungrep (and you have added a progressbar to the statusbar) - why ungrep became almost twice as slow as it used to be?