"Stable FOV" is a very simple client sided mod that disable the dynamic FOV (that make your FOV stay the same.) It's meant for the old mc versions that has no settings about that.
In short, hen you sprint or have some potions effect, your FOV use to change, but with this mod, it will stay the same.
Example of having no FOV when sprinting:
You can quickly toggle the mod with a default keybind set to "K". It also supports mouse macro
Feel free to include this mod in any modpack published on curseforge!
