- Open
about:config
in Firefox - Set the following values
- Restart Firefox
browser.snapshots.limit 5
browser.gesture.pinch.in cmd_fullZoomReduce
browser.gesture.pinch.out cmd_fullZoomEnlarge
browser.gesture.pinch.latched false
browser.gesture.pinch.threshold 35
You can double tap with two fingers in trackpad to reset zoom level.
These changes are no longer needed in recent Firefox as pinch-zooming support was added in version 83.0 for Windows and macOS and 88.0 for Linux.
I never tried using gestures in Linux but there is a post in Reddit that might be useful.