I've never looked at go code before (now I'm king of interested!), but I scanned the butler repo and saw filtering.go. I was looking at the CustomIgnorePatterns variable at first but eventually realized that's the command-line option and the PresetFilter function must be imported from the lake repo listed at top. Reading code is such a rabbit hole!
Viewing post in Butler and git repositories
Oh my.... That sounds embarrassing... Thumbs up for admitting this openly though...
I was recently trying to sort out the code of my old LAURA II engine (used in two RPGs hosted here on itch), and there I know I wrote that code before digging through it, and I wonder what I was thinking when I wrote that crap. Now that is not the reason why the two games this concerns (Star Story and The Fairy Tale REVAMPED) are about to be rewritten in a new engine (it has more to do with the language I used... The compiler refuses to work on me, and I want to make sure I can preserve those games for the future) anyway, but as that did require me to analyze my own code, I hate myself.