From what I can tell, Robigalia appears to be what he calls the "user space" component of an operating system based on the sel4 kernel, written in Rust. Sel4 is a "the world's first operating-system kernel with an end-to-end proof of implementation correctness and security enforcement".

Robigalia was a festival of propitation for the god Robigus, or Robigo (the gender of the god is ambiguous), a personification-type deity of crop disease. A thematic colour was of the festival is red, and Robigo was also the name at the time for what we call "wheat rust"[0], a potentially devistating crop disease.

So we have both the prevention of disease (Sel4) and the thematic presence of Rust.

[0] https://en.wikipedia.org/wiki/Wheat_leaf_rust

Unfortunately I can't take the credit for the (IMO) brilliant name. For over two weeks in ~September 2015 I was wracking my brain for a decent name and one of my fellow students came up with it. Lots of great name-based tie-ins.

Great explanation. Makes sense. Originally thought the name was weird but now it's extra clever.

It was a festival to fight a blight called "wheat rust" and it is an OS that promotes the use of Rust.