I remember reading about this change a few months ago on Plasma developer Nate Graham’s weekly update:
This week in KDE: SDDM – Adventures in Linux and KDE
User Interface Improvements
Dolphin now hides apps’ temp files and backup files (i.e. the kind of useless files that end in
~or#) unless actively showing hidden files (Méven Car, Dolphin 23.08. Link). This is a 23 year old feature request!
I had a quick scan-read of the bug report in the above quote - it looks like there might be an option available for those who want to keep *.bak & *.old files visible:
Comment 81
Just wanted to note: To unhide any of the file extensions affected by this change / Dolphin 23.08, use “File Associations” in System Settings to create a new file type for them. To the contrary, removing *.old and *.bak from the “application/x-trash” association still kept them hidden (which makes sense since the file types probably fell back to the system association, which is still “application/x-trash”)Might be stating the obvious, but I think this tip might help someone stumbling into this in future. I was one of the users purposefully renaming files to end in *.bak or *.old and naturally would like to keep them visible.