Same problem here, downloaded from the assetlib menu
core/extension/gdextension.cpp:593 - GDExtension configuration file must contain a "configuration/compatibility_minimum" key: res://addons/godot-git-plugin/git_plugin.gdextension
Failed loading resource: res://addons/godot-git-plugin/git_plugin.gdextension. Make sure resources have been imported by opening the project in the editor at least once.
Same problem here, downloaded from the assetlib menu
It appears the issue I'm talking about is already in another issue: https://github.com/godotengine/godot-git-plugin/issues/196