Creating a new mirror with historical stable releases?

[9numbernine9]

Hello!

I'm trying to set up a new Panamax mirror and I want to include the last several stable Rust toolchains as part of the mirroring process; at the time of this writing 1.79.0 is the most recent Rust stable release, but I'd also like my mirror to have the stable releases going back to 1.77.0 (i.e. 1.79.0, 1.78.0, 1.77.2, 1.77.1, 1.77.0). In my mirror.toml file I've set the following:

keep_latest_stables = 5

... But it seems like this does quite what I'm expecting. Under the dist/ directory I see that a channel-rust-stable.toml file was created that correctly points to the current stable release, but there's no other .toml files that point to any of the older stable releases (e.g. channel-rust-1.78.toml). Looking through the code I don't see very many references to the rustup.keep_latest_stables symbol so I'm not quite sure how this feature is supposed to work. What I was expecting to see is a .toml file for each stable release being kept by Panamax, and each of those files would contain the necessary URLs to download those versions.

Is it possible to bootstrap a new Panamax mirror in this way?