rustc_back has long since been renamed to rustc_target

Author: tshepang

src/high-level-overview.md

@@ -8,7 +8,7 @@ standard library and the compiler.  This document, of course, focuses
 on the latter.
 
 Rustc consists of a number of crates, including `syntax`,
-`rustc`, `rustc_back`, `rustc_codegen`, `rustc_driver`, and
+`rustc`, `rustc_target`, `rustc_codegen`, `rustc_driver`, and
 many more. The source for each crate can be found in a directory
 like `src/libXXX`, where `XXX` is the crate name.
 
@@ -139,4 +139,4 @@ take:
 
 [query model]: query.html
 [high-level intermediate representation]: hir.html
-[lowering]: lowering.html
+[lowering]: lowering.html