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diff --git a/doc/README.md b/doc/README.md
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--- a/doc/README.md
+++ b/doc/README.md
@@ -1,5 +1,4 @@
-
-# Nixpkgs/doc
+# Contributing to the Nixpkgs manual
 
 This directory houses the sources files for the Nixpkgs manual.
 
@@ -7,6 +6,110 @@ You can find the [rendered documentation for Nixpkgs `unstable` on nixos.org](ht
 
 [Docs for Nixpkgs stable](https://nixos.org/manual/nixpkgs/stable/) are also available.
 
-If you want to contribute to the documentation, [here's how to do it](https://nixos.org/manual/nixpkgs/unstable/#chap-contributing).
-
 If you're only getting started with Nix, go to [nixos.org/learn](https://nixos.org/learn).
+
+## Contributing to this documentation
+
+You can quickly check your edits with `nix-build`:
+
+```ShellSession
+$ cd /path/to/nixpkgs
+$ nix-build doc
+```
+
+If the build succeeds, the manual will be in `./result/share/doc/nixpkgs/manual.html`.
+
+### devmode
+
+The shell in the manual source directory makes available a command, `devmode`.
+It is a daemon, that:
+1. watches the manual's source for changes and when they occur — rebuilds
+2. HTTP serves the manual, injecting a script that triggers reload on changes
+3. opens the manual in the default browser
+
+## Syntax
+
+As per [RFC 0072](https://github.com/NixOS/rfcs/pull/72), all new documentation content should be written in [CommonMark](https://commonmark.org/) Markdown dialect.
+
+Additional syntax extensions are available, all of which can be used in NixOS option documentation. The following extensions are currently used:
+
+#### Tables
+
+Tables, using the [GitHub-flavored Markdown syntax](https://github.github.com/gfm/#tables-extension-).
+
+#### Anchors
+
+Explicitly defined **anchors** on headings, to allow linking to sections. These should be always used, to ensure the anchors can be linked even when the heading text changes, and to prevent conflicts between [automatically assigned identifiers](https://github.com/jgm/commonmark-hs/blob/master/commonmark-extensions/test/auto_identifiers.md).
+
+It uses the widely compatible [header attributes](https://github.com/jgm/commonmark-hs/blob/master/commonmark-extensions/test/attributes.md) syntax:
+
+```markdown
+## Syntax {#sec-contributing-markup}
+```
+
+> **Note**
+> NixOS option documentation does not support headings in general.
+
+#### Inline Anchors
+
+Allow linking arbitrary place in the text (e.g. individual list items, sentences…).
+
+They are defined using a hybrid of the link syntax with the attributes syntax known from headings, called [bracketed spans](https://github.com/jgm/commonmark-hs/blob/master/commonmark-extensions/test/bracketed_spans.md):
+
+```markdown
+- []{#ssec-gnome-hooks-glib} `glib` setup hook will populate `GSETTINGS_SCHEMAS_PATH` and then `wrapGAppsHook` will prepend it to `XDG_DATA_DIRS`.
+```
+
+#### Automatic links
+
+If you **omit a link text** for a link pointing to a section, the text will be substituted automatically. For example `[](#chap-contributing)`.
+
+This syntax is taken from [MyST](https://myst-parser.readthedocs.io/en/latest/using/syntax.html#targets-and-cross-referencing).
+
+#### Roles
+
+If you want to link to a man page, you can use `` {manpage}`nix.conf(5)` ``. The references will turn into links when a mapping exists in [`doc/manpage-urls.json`](./manpage-urls.json).
+
+A few markups for other kinds of literals are also available:
+
+- `` {command}`rm -rfi` ``
+- `` {env}`XDG_DATA_DIRS` ``
+- `` {file}`/etc/passwd` ``
+- `` {option}`networking.useDHCP` ``
+- `` {var}`/etc/passwd` ``
+
+These literal kinds are used mostly in NixOS option documentation.
+
+This syntax is taken from [MyST](https://myst-parser.readthedocs.io/en/latest/syntax/syntax.html#roles-an-in-line-extension-point). Though, the feature originates from [reStructuredText](https://www.sphinx-doc.org/en/master/usage/restructuredtext/roles.html#role-manpage) with slightly different syntax.
+
+#### Admonitions
+
+Set off from the text to bring attention to something.
+
+It uses pandoc’s [fenced `div`s syntax](https://github.com/jgm/commonmark-hs/blob/master/commonmark-extensions/test/fenced_divs.md):
+
+```markdown
+::: {.warning}
+This is a warning
+:::
+```
+
+The following are supported:
+
+- [`caution`](https://tdg.docbook.org/tdg/5.0/caution.html)
+- [`important`](https://tdg.docbook.org/tdg/5.0/important.html)
+- [`note`](https://tdg.docbook.org/tdg/5.0/note.html)
+- [`tip`](https://tdg.docbook.org/tdg/5.0/tip.html)
+- [`warning`](https://tdg.docbook.org/tdg/5.0/warning.html)
+
+#### [Definition lists](https://github.com/jgm/commonmark-hs/blob/master/commonmark-extensions/test/definition_lists.md)
+
+For defining a group of terms:
+
+```markdown
+pear
+:   green or yellow bulbous fruit
+
+watermelon
+:   green fruit with red flesh
+```