Quick Tailscale question / how to install alternate repo?

From other discussions here, it seems like the Tailscale add-on from https://github.com/tsujamin/hass-addons/tree/main/tailscale seems better (i.e. more config options, more features, more frequent releases, up-to-date client, etc.) than the official add-on that appears to be less full-featured and isn’t super updated.

I am trying to use the alternate repo via the add-on store by adding a new repository from the “manage add-on repositories screen”, but when I try to add the repo, hass is throwing an error:

It looks like the system is trying to add an extra “/” at the end of the repository URL, which is causing a repository not found error? Is there a way to prevent this or some setting I need to change?

As shown in the screenshot, I do have another custom repository installed, so not sure if this is an isolated issue or how to go about debugging it. Any direction/ideas would be much appreciated!