There's support and "support".
MacPorts has some level of support for PowerPC, but anything that isn't in the most recent ~3-4 releases is likely to be cut off from any number of packages at useful versions. (There's substantial work down to support Rust on much older versions of macOS, but there's also versions above which Rust has cut off older macOS versions.)
I believe that there's a recommended stream for when you need older versions support, but it's definitely a secondary target from what I've been reading on the MLs.