Teapot Repos is a guide to Teapot repositories that spring up.
Lars H: Shouldn't that be "Teacup" instead, i.e., what matters is not the exact server software, but whether the client can make use of the site? OTOH, as long as the Tea??? system remains closed source without published interfaces it probably doesn't matter; there cannot be any alternatives to client or server.
Please have in mind, Teacup and (ActiveState's Tcl Dev Kit's Teapot too) is not able to connect to https!
(Update on the open-sourced tool to get such functionality is outstanding...)
If You need it anyway, I (TWu) can provide a 1 GiBy zip-file together with a Tcl-script.
It is a complete repo copy at latest state (from about 2015/2016, as no longer maintained from ActiveState),
and is used offline afterwards as a local web-server (to local file redirection) for Teacup.
Inside are all libraries, packages, sources, demos, programs etc. for all platforms Windows, Linux, MacOS etc. like the original repo has.
It is compatible with ActiveTcl 8.6.4.1 and Tcl Dev Kit 5.4.1 (both: the last official versions before end-of-support/life and open-sourced).