diff --git a/Documentation/config.txt b/Documentation/config.txt
index f1f409d24b..77a2b16416 100644
--- a/Documentation/config.txt
+++ b/Documentation/config.txt
@@ -14,14 +14,72 @@ dot-separated segment and the section name is everything before the last
 dot. The variable names are case-insensitive and only alphanumeric
 characters are allowed. Some variables may appear multiple times.
 
+Syntax
+~~~~~~
+
 The syntax is fairly flexible and permissive; whitespaces are mostly
-ignored. The '#' and ';' characters begin comments to the end of line,
-blank lines are ignored, lines containing strings enclosed in square
-brackets start sections and all the other lines are recognized
-as setting variables, in the form 'name = value'. If there is no equal
-sign on the line, the entire line is taken as 'name' and the variable
-is recognized as boolean "true". String values may be entirely or partially
-enclosed in double quotes; some variables may require special value format.
+ignored.  The '#' and ';' characters begin comments to the end of line,
+blank lines are ignored.
+
+The file consists of sections and variables.  A section begins with
+the name of the section in square brackets and continues until the next
+section begins.  Section names are not case sensitive.  Only alphanumeric
+characters, '`-`' and '`.`' are allowed in section names.  Each variable
+must belong to some section, which means that there must be section
+header before first setting of a variable.
+
+Sections can be further divided into subsections.  To begin a subsection
+put its name in double quotes, separated by space from the section name,
+in the section header, like in example below:
+
+--------
+	[section "subsection"]
+
+--------
+
+Subsection names can contain any characters (doublequote '`"`', backslash
+'`\`' and newline have to be entered escaped as '`\"`', '`\\`' and '`\n`',
+respecitvely) and are case sensitive.  Section header cannot span multiple
+lines.  Variables may belong directly to a section or to a given subsection.
+You can have `[section]` if you have `[section "subsection"]`, but you
+don't need to.
+
+There is also (case insensitive) alternative `[section.subsection]` syntax.
+In this syntax subsection names follow the same restrictions as for section
+name.
+
+All the other lines are recognized as setting variables, in the form
+'name = value'.  If there is no equal sign on the line, the entire line
+is taken as 'name' and the variable is recognized as boolean "true".
+The variable names are case-insensitive and only alphanumeric
+characters and '`-`' are allowed.  There can be more than one value
+for a given variable; we say then that variable is multivalued.
+
+Leading and trailing whitespace in a variable value is discarded.
+Internal whitespace within a variable value is retained verbatim.
+
+The values following the equals sign in variable assign are all either
+a string, an integer, or a boolean.  Boolean values may be given as yes/no,
+0/1 or true/false.  Case is not significant in boolean values, when
+converting value to the canonical form using '--bool' type specifier;
+`git-repo-config` will ensure that the output is "true" or "false".
+
+String values may be entirely or partially enclosed in double quotes.
+You need to enclose variable value in double quotes if you want to
+preserve leading or trailing whitespace, or if variable value contains
+beginning of comment characters (if it contains '#' or ';').
+Double quote '`"`' and backslash '`\`' characters in variable value must
+be escaped: use '`\"`' for '`"`' and '`\\`' for '`\`'.
+
+The following escape sequences (beside '`\"`' and '`\\`') are recognized:
+'`\n`' for newline character (NL), '`\t`' for horizontal tabulation (HT, TAB)
+and '`\b`' for backspace (BS).  No other char escape sequence, nor octal
+char sequences are valid.
+
+Variable value ending in a '`\`' is continued on the next line in the
+customary UNIX fashion.
+
+Some variables may require special value format.
 
 Example
 ~~~~~~~
@@ -40,6 +98,10 @@ Example
 		remote = origin
 		merge = refs/heads/devel
 
+	# Proxy settings
+	[core]
+		gitProxy="ssh" for "ssh://kernel.org/"
+		gitProxy=default-proxy ; for the rest
 
 Variables
 ~~~~~~~~~