I believe there’s one extra “detail” in addition to this. Of my three Manjaro installations, two of them have the same packages installed via the AUR. However, only one of them had this issue with wxgtk2.
Here’s what I think might have occurred with myself and others:
In the past, there might have been an AUR PKGBUILD with wxgtk2 as a dependency. Installing the (mystery) package from the AUR naturally pulled in wxgtk2 from the repositories.
Over time, this particular software from the AUR no longer required wxgtk2, yet even after several updates, wxgtk2 was never removed automatically. It just remained installed in the system all alone, not required by anything else.
Upon trying to determine which package is using wxgtk2 as a dependency, it’s revealed that no packages require it. (Which adds to the confusions above.) Even still, trying to update via Pamac will abort unless there is manual intervention to remove wxgtk2.
The difference between my two systems (one with this “issue” and the other without this issue) could be due to the fact that I initially installed packages from the AUR at a later date on the computer without wxgtk2. Hence, wxgtk2 was never pulled into this computer.
In fact, on the “behaving” system, my pacman history shows zero entries for wxgtk2, from the day I installed Manjaro all the way up until today.
UPDATE: I found the culprit in my situation. It was the package amule, which is on the official Arch Linux repositories, but in September 2021 they later switched its dependency from wxgtk2 to wxgtk3.
Post with further explanation: Recent stable updates and wxgtk2: what happened? - #10 by winnie