Currently, running the installer for the Windows nightly requires admin permissions. This is understandable if Zadig has to be installed. However, if Zadig is not needed (i.e. no device will ever be attached) or already installed, this is bad. Putting the sigrok folder in a system-protected area (e.g. C:\Programs) also prevents users from adding/editing PDs without admin permissions. I didn't check this but if I'm not mistaken then this limitation also applies even when installing it somewhere else, simply because the installer runs as admin and so the regular user account probably has no write access. If possible, the installer should be executable without admin permissions and only request them if the user desires to have Zadig installed.
I'll look into this, not sure if it's fixable within one .exe installer file, might need to provide multiple. Not sure yet. This is unrelated to Zadig btw., it's just another .exe which is sitting around, that's not the reason to make the installer require admin permissions.