1366x768 is very common resolution in laptops.
Same issue, reported by Ubuntu user .
Do you have a patch to submit?
Yes 1366x768 in not cvt compliant, seems it would be either 1360x768 or 1368x768 (apparently a quick search on google shows it's a problem not just for Xwayland).
But I am tempted to ask, why does it matter?
The root window is correctly sized to 1366x768, so is it just about the mode name in xrandr (which is called 1360x768) ?
It does not affect Chromium for example. But does matter to all fullscreen applications (all games both native and Wine are affected) that are running in XWayland as they set 1360x768 resolution and draw on 1366x768 root window and that results in blurriness on parts that does not match pixel grid and jagginess on parts that do.
Reworked patch has been accepted (feels great):
Thanks to Olivier Fourdan for valuable input and care!