When we last left off, the issue tracker devs stated that the properties manager could handle atomic rotations in PCB Editor via the Property Editor to set all selected objects to a specific rotation orientation relative to the grid.
To my knowledge, there is no means to rotate/mirror in-place all items relative to their present orientation. There is no means to mirror in-place all items to an absolute mirroring.
The request has since been clarified to allow for rotations/mirroring in-place relative their individual present positions or absolutely, to increase function scope to apply to symbols/footprints/etcetera, and to add the means to do so to associated areas : text/graphics wizard, positioning wizard, hotkey list, right-click menu.
I read your posted Issue/Update and glean that it may never happen (I could be wrong)…
That said, doing it on a PCB/Schematic/etc is simple enough using common Text-Editor that features Find-All and Replace-All
Also, this can be done using Search/Replace features of Python.
And, can do that in a Homemade App or in Kicad’s Python Console (PCB and Schematic)… Or, from your system’s default Python IDE
Two Example Videos:
I used my (homemade) App
Used Python IDE
There are only 8 (eight) lines of Code - you can read the code in the video.
You can set a Path in the code if you know how but, it’s simple to just place the Python Code file in the Kicad project of interest and run it - it will edit the files in that folder…
Details of further usage of Python’s Search/Replace and File selection are plentiful on internet…
Good luck
Note: The Position Data is from the Footprint and shown in Video’s