@fniephaus The reason that some of the Squeak builds fail is that the SqueakSSL plugin doesn't work. I haven't spent the time to look into it in detail, so I don't know why exactly. It's the #primitiveSSLCreate that fails (module loading works).
I suspect that the issue lies with a dependency version, e.g., openssl, since the Squeak 6 build is fine.
I don't think we can do anything about the situation, except for excluding the builds from GH. What do you think?