Mouser is an open-source alternative to Logitech's Options+ software, allowing users to remap buttons and customize settings for their Logitech mice without relying on proprietary software. The project aims to provide a fully local, telemetry-free, and cloud-free solution. Mouser supports various Logitech mouse models, including the MX Master and MX Anywhere families, and is available for Windows, macOS, and Linux. The software offers features such as button remapping, per-application profiles, and custom keyboard shortcuts.