“Jiri integrates repositories intelligently”
is the official description as well as a recursive acronym for jiri.
It is a multi-repo management tool used internally at Google for their Fuchsia OS development. The project manifest format is pretty much like repo, which is commonly used for Android development and was later adopted by other communities like CoreOS.
I came across Fuchsia even before its kernel was renamed to Zircon, and at that time, the Fuchsia OS itself is pretty much unusable. But I found jiri particularly useful for my own projects. Since then, I started using jiri for my own large projects that requires splitting repositories and gather them together to build (like my own libraries, my build tools, etc.)
I’m currently taking the Undergrad OS course at UW-Madison this semester (CS537: Operating System).
Our professor is REMZI H. ARPACI-DUSSEAU who is apparently very famous in the OS industry (at least that’s what I think considering the google search result).