FOSS performance overlay "GOverlay" has been updated to version 1.2. This update adds a winesync option, a new Vulkan Present mode option, a negative offset option for FPS limits, four bug fixes, and more. The code is licensed using GPLv3.0. GOverlay is an opensource project that aims to create a Graphical UI to help manage Linux overlays. The project can be found in various Linux distro repos.
The source code can be found on Github:
https://github.com/benjamimgois/goverlay
If you wish to help the project financially you can donate to the lead developer Benjamim Góis Ildefonso da silva through Paypal: