Which I just finished updating to 1.0. But it is currently lacking in breadth of API, so if you start using it let us know what you are missing. In the meantime https://github.com/n0-computer/iroh-ffi has the other language bindings with a more comprehensive API
Yes, but libp2p was mainly designed around the limitations of tcp, as quic simply wasn't there yet when the design started. Iroh gets the benefit of having been designed and built from the ground up, based on quic.
Tailscale is built to be global to your device, while iroh is built to be embedded into each application. This allows application developers and users a much more fine grained and bespoke setup, than having a single global bridge.
While it doesn't solve all the issues that come up through the current segmentation, it is very much possible today to assemble components that let you forget about segmentation while you use it.
And it is designed from the ground up, to use existing internet technologies, while avoiding the lock in and dependencies on browser vendors or other large players.
As others have already mentioned, iroh the core library and protocol is fully open source. But to finance the development of it, we offer additional services to make it easier to deploy and run it, especially for larger or more specialized use caes.