As of Godot 4.2 the editor has a Windows-specific workaround for loading extension libraries.
Before the extension library is loaded the Godot editor creates a temp copy of the extension library `.dll` file with a `~` prefix (e.g. `example.dll` => `~example.dll`).
When the extension library is unloaded the Godot editor deletes the temp copy.
These copied `~*.dll` files are temporary and should be ignored.

References:

Godot 4.2 changelog
https://godotengine.org/article/godot-4-2-arrives-in-style/#gdextension

Godot PR #80188 GDExtension: Copy DLL to a temp file before opening
godotengine/godot#80188