diff --git a/Documentation/technical/api-gitattributes.txt b/Documentation/technical/api-gitattributes.txt
deleted file mode 100644
index 45f0df600f..0000000000
--- a/Documentation/technical/api-gitattributes.txt
+++ /dev/null
@@ -1,154 +0,0 @@
-gitattributes API
-=================
-
-gitattributes mechanism gives a uniform way to associate various
-attributes to set of paths.
-
-
-Data Structure
---------------
-
-`struct git_attr`::
-
-	An attribute is an opaque object that is identified by its name.
-	Pass the name to `git_attr()` function to obtain the object of
-	this type.  The internal representation of this structure is
-	of no interest to the calling programs.  The name of the
-	attribute can be retrieved by calling `git_attr_name()`.
-
-`struct attr_check_item`::
-
-	This structure represents one attribute and its value.
-
-`struct attr_check`::
-
-	This structure represents a collection of `attr_check_item`.
-	It is passed to `git_check_attr()` function, specifying the
-	attributes to check, and receives their values.
-
-
-Attribute Values
-----------------
-
-An attribute for a path can be in one of four states: Set, Unset,
-Unspecified or set to a string, and `.value` member of `struct
-attr_check_item` records it.  There are three macros to check these:
-
-`ATTR_TRUE()`::
-
-	Returns true if the attribute is Set for the path.
-
-`ATTR_FALSE()`::
-
-	Returns true if the attribute is Unset for the path.
-
-`ATTR_UNSET()`::
-
-	Returns true if the attribute is Unspecified for the path.
-
-If none of the above returns true, `.value` member points at a string
-value of the attribute for the path.
-
-
-Querying Specific Attributes
-----------------------------
-
-* Prepare `struct attr_check` using attr_check_initl()
-  function, enumerating the names of attributes whose values you are
-  interested in, terminated with a NULL pointer.  Alternatively, an
-  empty `struct attr_check` can be prepared by calling
-  `attr_check_alloc()` function and then attributes you want to
-  ask about can be added to it with `attr_check_append()`
-  function.
-
-* Call `git_check_attr()` to check the attributes for the path.
-
-* Inspect `attr_check` structure to see how each of the
-  attribute in the array is defined for the path.
-
-
-Example
--------
-
-To see how attributes "crlf" and "ident" are set for different paths.
-
-. Prepare a `struct attr_check` with two elements (because
-  we are checking two attributes):
-
-------------
-static struct attr_check *check;
-static void setup_check(void)
-{
-	if (check)
-		return; /* already done */
-	check = attr_check_initl("crlf", "ident", NULL);
-}
-------------
-
-. Call `git_check_attr()` with the prepared `struct attr_check`:
-
-------------
-	const char *path;
-
-	setup_check();
-	git_check_attr(path, check);
-------------
-
-. Act on `.value` member of the result, left in `check->items[]`:
-
-------------
-	const char *value = check->items[0].value;
-
-	if (ATTR_TRUE(value)) {
-		The attribute is Set, by listing only the name of the
-		attribute in the gitattributes file for the path.
-	} else if (ATTR_FALSE(value)) {
-		The attribute is Unset, by listing the name of the
-		attribute prefixed with a dash - for the path.
-	} else if (ATTR_UNSET(value)) {
-		The attribute is neither set nor unset for the path.
-	} else if (!strcmp(value, "input")) {
-		If none of ATTR_TRUE(), ATTR_FALSE(), or ATTR_UNSET() is
-		true, the value is a string set in the gitattributes
-		file for the path by saying "attr=value".
-	} else if (... other check using value as string ...) {
-		...
-	}
-------------
-
-To see how attributes in argv[] are set for different paths, only
-the first step in the above would be different.
-
-------------
-static struct attr_check *check;
-static void setup_check(const char **argv)
-{
-	check = attr_check_alloc();
-	while (*argv) {
-		struct git_attr *attr = git_attr(*argv);
-		attr_check_append(check, attr);
-		argv++;
-	}
-}
-------------
-
-
-Querying All Attributes
------------------------
-
-To get the values of all attributes associated with a file:
-
-* Prepare an empty `attr_check` structure by calling
-  `attr_check_alloc()`.
-
-* Call `git_all_attrs()`, which populates the `attr_check`
-  with the attributes attached to the path.
-
-* Iterate over the `attr_check.items[]` array to examine
-  the attribute names and values.  The name of the attribute
-  described by an `attr_check.items[]` object can be retrieved via
-  `git_attr_name(check->items[i].attr)`.  (Please note that no items
-  will be returned for unset attributes, so `ATTR_UNSET()` will return
-  false for all returned `attr_check.items[]` objects.)
-
-* Free the `attr_check` struct by calling `attr_check_free()`.
diff --git a/attr.h b/attr.h
index b0378bfe5f..404548f028 100644
--- a/attr.h
+++ b/attr.h
@@ -1,9 +1,121 @@
 #ifndef ATTR_H
 #define ATTR_H
 
+/**
+ * gitattributes mechanism gives a uniform way to associate various attributes
+ * to set of paths.
+ *
+ *
+ * Querying Specific Attributes
+ * ----------------------------
+ *
+ * - Prepare `struct attr_check` using attr_check_initl() function, enumerating
+ *   the names of attributes whose values you are interested in, terminated with
+ *   a NULL pointer.  Alternatively, an empty `struct attr_check` can be
+ *   prepared by calling `attr_check_alloc()` function and then attributes you
+ *   want to ask about can be added to it with `attr_check_append()` function.
+ *
+ * - Call `git_check_attr()` to check the attributes for the path.
+ *
+ * - Inspect `attr_check` structure to see how each of the attribute in the
+ *   array is defined for the path.
+ *
+ *
+ * Example
+ * -------
+ *
+ * To see how attributes "crlf" and "ident" are set for different paths.
+ *
+ * - Prepare a `struct attr_check` with two elements (because we are checking
+ *   two attributes):
+ *
+ * ------------
+ * static struct attr_check *check;
+ * static void setup_check(void)
+ * {
+ * 	if (check)
+ * 		return; // already done
+ * check = attr_check_initl("crlf", "ident", NULL);
+ * }
+ * ------------
+ *
+ * - Call `git_check_attr()` with the prepared `struct attr_check`:
+ *
+ * ------------
+ * const char *path;
+ *
+ * setup_check();
+ * git_check_attr(path, check);
+ * ------------
+ *
+ * - Act on `.value` member of the result, left in `check->items[]`:
+ *
+ * ------------
+ * const char *value = check->items[0].value;
+ *
+ * if (ATTR_TRUE(value)) {
+ * The attribute is Set, by listing only the name of the
+ * attribute in the gitattributes file for the path.
+ * } else if (ATTR_FALSE(value)) {
+ * The attribute is Unset, by listing the name of the
+ *         attribute prefixed with a dash - for the path.
+ * } else if (ATTR_UNSET(value)) {
+ * The attribute is neither set nor unset for the path.
+ * } else if (!strcmp(value, "input")) {
+ * If none of ATTR_TRUE(), ATTR_FALSE(), or ATTR_UNSET() is
+ *         true, the value is a string set in the gitattributes
+ * file for the path by saying "attr=value".
+ * } else if (... other check using value as string ...) {
+ * ...
+ * }
+ * ------------
+ *
+ * To see how attributes in argv[] are set for different paths, only
+ * the first step in the above would be different.
+ *
+ * ------------
+ * static struct attr_check *check;
+ * static void setup_check(const char **argv)
+ * {
+ *     check = attr_check_alloc();
+ *     while (*argv) {
+ *         struct git_attr *attr = git_attr(*argv);
+ *         attr_check_append(check, attr);
+ *         argv++;
+ *     }
+ * }
+ * ------------
+ *
+ *
+ * Querying All Attributes
+ * -----------------------
+ *
+ * To get the values of all attributes associated with a file:
+ *
+ * - Prepare an empty `attr_check` structure by calling `attr_check_alloc()`.
+ *
+ * - Call `git_all_attrs()`, which populates the `attr_check` with the
+ * attributes attached to the path.
+ *
+ * - Iterate over the `attr_check.items[]` array to examine the attribute
+ * names and values. The name of the attribute described by an
+ * `attr_check.items[]` object can be retrieved via
+ * `git_attr_name(check->items[i].attr)`. (Please note that no items will be
+ * returned for unset attributes, so `ATTR_UNSET()` will return false for all
+ * returned `attr_check.items[]` objects.)
+ *
+ * - Free the `attr_check` struct by calling `attr_check_free()`.
+ */
+
 struct index_state;
 
-/* An attribute is a pointer to this opaque structure */
+/**
+ * An attribute is an opaque object that is identified by its name. Pass the
+ * name to `git_attr()` function to obtain the object of this type.
+ * The internal representation of this structure is of no interest to the
+ * calling programs. The name of the attribute can be retrieved by calling
+ * `git_attr_name()`.
+ */
 struct git_attr;
 
 /* opaque structures used internally for attribute collection */
@@ -21,21 +133,36 @@ const struct git_attr *git_attr(const char *);
 extern const char git_attr__true[];
 extern const char git_attr__false[];
 
-/* For public to check git_attr_check results */
+/**
+ * Attribute Values
+ * ----------------
+ *
+ * An attribute for a path can be in one of four states: Set, Unset, Unspecified
+ * or set to a string, and `.value` member of `struct attr_check_item` records
+ * it. The three macros check these, if none of them returns true, `.value`
+ * member points at a string value of the attribute for the path.
+ */
+
+/* Returns true if the attribute is Set for the path. */
 #define ATTR_TRUE(v) ((v) == git_attr__true)
+
+/* Returns true if the attribute is Unset for the path. */
 #define ATTR_FALSE(v) ((v) == git_attr__false)
+
+/* Returns true if the attribute is Unspecified for the path. */
 #define ATTR_UNSET(v) ((v) == NULL)
 
-/*
- * Send one or more git_attr_check to git_check_attrs(), and
- * each 'value' member tells what its value is.
- * Unset one is returned as NULL.
- */
+/* This structure represents one attribute and its value. */
 struct attr_check_item {
 	const struct git_attr *attr;
 	const char *value;
 };
 
+/**
+ * This structure represents a collection of `attr_check_item`. It is passed to
+ * `git_check_attr()` function, specifying the attributes to check, and
+ * receives their values.
+ */
 struct attr_check {
 	int nr;
 	int alloc;
