If my memory serves me right, Rust was initially created FOR Servo. Rust came into existence because Mozilla wanted a memory safe browser engine and couldn’t achieve that with existing languages without garbage collection.
Basically how languages like Swift, D, Chapel, OCaml, Haskell are now approaching it, using the type system in addition to automatic memory management mechanisms, not just one way.
Rust pre-1.0 was full of sigils, Perl style, on what kind of memory a type related to to.