Feature Request - Mirror Mode
I don't know if there's a forum for feature requests, but I have one. If there's a better place for this, please let me know.
I think it would be a great feature to be able to flip a model from left to right from the printer settings. It would be an easy way to create a variation of a model without having to re-slice, and should be easy to implement by just negating the x-axis position and velocity values. The purge line would end up on the left side, but that's moved in the past (from the MK4, IIRC), and I can't think of any other consequence.
RE: Feature Request - Mirror Mode
You can already do this in the slicer. Just right click on an object and select which axis you want to mirror on.
If you, for example, only have the g-code then you can create a script to do this by avoiding the purge line (where Y is negative) and doing 250 - X on the G90 lines. Or just give the g-code to an AI and ask it to mirror the code.
Another way to do it (if you want to mirror on both X and Y) is to go into the buddy board and swap around the X and Y cables.
If you haven't already done so, you should add a feature request here: https://github.com/prusa3d/Prusa-Firmware-Buddy/issues/5297 warning is that there is an extremely high probability of it getting ignored.
To add this as a firmware option is certainly doable but a little more complicated.