diff --git a/docs/user/manual.adoc b/docs/user/manual.adoc
index d4121b4011..8ed7b041fa 100644
--- a/docs/user/manual.adoc
+++ b/docs/user/manual.adoc
@@ -18,6 +18,9 @@ The LSP allows various code editors, like VS Code, Emacs or Vim, to implement se
 [.lead]
 To improve this document, send a pull request: +
 https://github.com/rust-analyzer/rust-analyzer/blob/master/docs/user/manual.adoc[https://github.com/rust-analyzer/.../manual.adoc]
+
+The manual is written in https://asciidoc.org[AsciiDoc] and includes some extra files which are generated from the source code. Run `cargo test` and `cargo xtask codegen` to create these and then `asciidoctor manual.adoc` to create an HTML copy.
+
 ====
 
 If you have questions about using rust-analyzer, please ask them in the https://users.rust-lang.org/c/ide/14["`IDEs and Editors`"] topic of Rust users forum.