For the first-time installation, you'll need to generate a self-signed certificate. The script below will generate and add a cert to your [TRCA store](https://docs.microsoft.com/en-us/windows-hardware/drivers/install/trusted-root-certification-authorities-certificate-store).
In order to install the MSIX package without using the Microsoft Store, sideloading apps needs to be enabled. This can be done by enabling `Developer Options > Sideload apps` or `Developer Options > Developer mode`.
`reinstall_msix.ps1` removes the current PowerToys installation, restarts explorer.exe (to update PowerRename and ImageResizer shell extension), builds `PowerToys-x64.msix` package, signs it with a PowerToys_TemporaryKey.pfx, and finally installs it.