diff --git a/poky/documentation/overview-manual/concepts.rst b/poky/documentation/overview-manual/concepts.rst
index 89a5eb4..5698d93 100644
--- a/poky/documentation/overview-manual/concepts.rst
+++ b/poky/documentation/overview-manual/concepts.rst
@@ -1570,7 +1570,7 @@
 scratch is attractive as it means all parts are built fresh and there is
 no possibility of stale data that can cause problems. When
 developers hit problems, they typically default back to building from
-scratch so they have a know state from the start.
+scratch so they have a known state from the start.
 
 Building an image from scratch is both an advantage and a disadvantage
 to the process. As mentioned in the previous paragraph, building from
@@ -1718,7 +1718,7 @@
 :term:`Build Directory`. The checksum (or
 signature) for a particular task needs to add the hashes of all the
 tasks on which the particular task depends. Choosing which dependencies
-to add is a policy decision. However, the effect is to generate a master
+to add is a policy decision. However, the effect is to generate a
 checksum that combines the basehash and the hashes of the task's
 dependencies.
 
@@ -1735,12 +1735,8 @@
        PRSERV_DUMPDIR PRSERV_DUMPFILE PRSERV_LOCKDOWN PARALLEL_MAKE \\
        CCACHE_DIR EXTERNAL_TOOLCHAIN CCACHE CCACHE_DISABLE LICENSE_PATH SDKPKGSUFFIX"
 
-The
-previous example excludes
-:term:`WORKDIR` since that variable
-is actually constructed as a path within
-:term:`TMPDIR`, which is on the
-whitelist.
+The previous example does not include :term:`WORKDIR` since that variable is
+actually constructed as a path within :term:`TMPDIR`, which is included above.
 
 The rules for deciding which hashes of dependent tasks to include
 through dependency chains are more complex and are generally
@@ -1800,7 +1796,7 @@
 directory tree such as the sysroot.
 
 The Yocto Project team has tried to keep the details of the
-implementation hidden in ``sstate`` class. From a user's perspective,
+implementation hidden in the :ref:`sstate <ref-classes-sstate>` class. From a user's perspective,
 adding shared state wrapping to a task is as simple as this
 :ref:`ref-tasks-deploy` example taken
 from the :ref:`deploy <ref-classes-deploy>` class::
@@ -1942,6 +1938,138 @@
 recipe-based approach, which would have to install the output from every
 task.
 
+Hash Equivalence
+----------------
+
+The above section explained how BitBake skips the execution of tasks
+whose output can already be found in the Shared State cache.
+
+During a build, it may often be the case that the output / result of a task might
+be unchanged despite changes in the task's input values. An example might be
+whitespace changes in some input C code. In project terms, this is what we define
+as "equivalence".
+
+To keep track of such equivalence, BitBake has to manage three hashes
+for each task:
+
+- The *task hash* explained earlier: computed from the recipe metadata,
+  the task code and the task hash values from its dependencies.
+  When changes are made, these task hashes are therefore modified,
+  causing the task to re-execute. The task hashes of tasks depending on this
+  task are therefore modified too, causing the whole dependency
+  chain to re-execute.
+
+- The *output hash*, a new hash computed from the output of Shared State tasks,
+  tasks that save their resulting output to a Shared State tarball.
+  The mapping between the task hash and its output hash is reported
+  to a new *Hash Equivalence* server. This mapping is stored in a database
+  by the server for future reference.
+
+- The *unihash*, a new hash, initially set to the task hash for the task.
+  This is used to track the *unicity* of task output, and we will explain
+  how its value is maintained.
+
+When Hash Equivalence is enabled, BitBake computes the task hash
+for each task by using the unihash of its dependencies, instead
+of their task hash.
+
+Now, imagine that a Shared State task is modified because of a change in
+its code or metadata, or because of a change in its dependencies.
+Since this modifies its task hash, this task will need re-executing.
+Its output hash will therefore be computed again.
+
+Then, the new mapping between the new task hash and its output hash
+will be reported to the Hash Equivalence server. The server will
+let BitBake know whether this output hash is the same as a previously
+reported output hash, for a different task hash.
+
+If the output hash is already known, BitBake will update the task's
+unihash to match the original task hash that generated that output.
+Thanks to this, the depending tasks will keep a previously recorded
+task hash, and BitBake will be able to retrieve their output from
+the Shared State cache, instead of re-executing them. Similarly, the
+output of further downstream tasks can also be retrieved from Shared
+Shate.
+
+If the output hash is unknown, a new entry will be created on the Hash
+Equivalence server, matching the task hash to that output.
+The depending tasks, still having a new task hash because of the
+change, will need to re-execute as expected. The change propagates
+to the depending tasks.
+
+To summarize, when Hash Equivalence is enabled, a change in one of the
+tasks in BitBake's run queue doesn't have to propagate to all the
+downstream tasks that depend on the output of this task, causing a
+full rebuild of such tasks, and so on with the next depending tasks.
+Instead, when the output of this task remains identical to previously
+recorded output, BitBake can safely retrieve all the downstream
+task output from the Shared State cache.
+
+.. note::
+
+   Having :doc:`/test-manual/reproducible-builds` is a key ingredient for
+   the stability of the task's output hash. Therefore, the effectiveness
+   of Hash Equivalence strongly depends on it.
+
+This applies to multiple scenarios:
+
+-  A "trivial" change to a recipe that doesn't impact its generated output,
+   such as whitespace changes, modifications to unused code paths or
+   in the ordering of variables.
+
+-  Shared library updates, for example to fix a security vulnerability.
+   For sure, the programs using such a library should be rebuilt, but
+   their new binaries should remain identical. The corresponding tasks should
+   have a different output hash because of the change in the hash of their
+   library dependency, but thanks to their output being identical, Hash
+   Equivalence will stop the propagation down the dependency chain.
+
+-  Native tool updates. Though the depending tasks should be rebuilt,
+   it's likely that they will generate the same output and be marked
+   as equivalent.
+
+This mechanism is enabled by default in Poky, and is controlled by three
+variables:
+
+-  :term:`bitbake:BB_HASHSERVE`, specifying a local or remote Hash
+   Equivalence server to use.
+
+-  :term:`BB_HASHSERVE_UPSTREAM`, when ``BB_HASHSERVE = "auto"``,
+   allowing to connect the local server to an upstream one.
+
+-  :term:`bitbake:BB_SIGNATURE_HANDLER`, which must be set  to ``OEEquivHash``.
+
+Therefore, the default configuration in Poky corresponds to the
+below settings::
+
+   BB_HASHSERVE = "auto"
+   BB_SIGNATURE_HANDLER = "OEEquivHash"
+
+Rather than starting a local server, another possibility is to rely
+on a Hash Equivalence server on a network, by setting::
+
+   BB_HASHSERVE = "<HOSTNAME>:<PORT>"
+
+.. note::
+
+   The shared Hash Equivalence server needs to be maintained together with the
+   Shared State cache. Otherwise, the server could report Shared State hashes
+   that only exist on specific clients.
+
+   We therefore recommend that one Hash Equivalence server be set up to
+   correspond with a given Shared State cache, and to start this server
+   in *read-only mode*, so that it doesn't store equivalences for
+   Shared State caches that are local to clients.
+
+   See the :term:`BB_HASHSERVE` reference for details about starting
+   a Hash Equivalence server.
+
+See the `video <https://www.youtube.com/watch?v=zXEdqGS62Wc>`__
+of Joshua Watt's `Hash Equivalence and Reproducible Builds
+<https://elinux.org/images/3/37/Hash_Equivalence_and_Reproducible_Builds.pdf>`__
+presentation at ELC 2020 for a very synthetic introduction to the
+Hash Equivalence implementation in the Yocto Project.
+
 Automatically Added Runtime Dependencies
 ========================================
 
diff --git a/poky/documentation/overview-manual/development-environment.rst b/poky/documentation/overview-manual/development-environment.rst
index d719ba6..fc193f3 100644
--- a/poky/documentation/overview-manual/development-environment.rst
+++ b/poky/documentation/overview-manual/development-environment.rst
@@ -163,9 +163,9 @@
 
    -  Be sure to always work in matching branches for both the selected
       BSP repository and the Source Directory (i.e. ``poky``)
-      repository. For example, if you have checked out the "master"
+      repository. For example, if you have checked out the "&DISTRO_NAME_NO_CAP;"
       branch of ``poky`` and you are going to use ``meta-intel``, be
-      sure to checkout the "master" branch of ``meta-intel``.
+      sure to checkout the "&DISTRO_NAME_NO_CAP;" branch of ``meta-intel``.
 
 In summary, here is where you can get the project files needed for
 development:
@@ -233,8 +233,8 @@
 open source projects do so.
 
 For the Yocto Project, a key individual called the "maintainer" is
-responsible for the integrity of the "master" branch of a given Git
-repository. The "master" branch is the "upstream" repository from which
+responsible for the integrity of the development branch of a given Git
+repository. The development branch is the "upstream" repository from which
 final or most recent builds of a project occur. The maintainer is
 responsible for accepting changes from other developers and for
 organizing the underlying branch structure to reflect release strategies
@@ -279,8 +279,8 @@
 ":ref:`dev-manual/common-tasks:submitting a change to the yocto project`"
 section in the Yocto Project Development Tasks Manual.
 
-In summary, there is a single point of entry for changes into a "master"
-or development branch of the Git repository, which is controlled by the
+In summary, there is a single point of entry for changes into the
+development branch of the Git repository, which is controlled by the
 project's maintainer. A set of developers independently
 develop, test, and submit changes to "contrib" areas for the maintainer
 to examine. The maintainer then chooses which changes are going to
@@ -311,7 +311,7 @@
    host. You can name these branches anything you like. It is helpful to
    give them names associated with the particular feature or change on
    which you are working. Once you are done with a feature or change and
-   have merged it into your local master branch, simply discard the
+   have merged it into your local development branch, simply discard the
    temporary branch.
 
 -  *Merge Changes:* The ``git merge`` command allows you to take the
@@ -348,7 +348,7 @@
 
 -  *Patch Workflow:* This workflow allows you to notify the maintainer
    through an email that you have a change (or patch) you would like
-   considered for the "master" branch of the Git repository. To send
+   considered for the development branch of the Git repository. To send
    this type of change, you format the patch and then send the email
    using the Git commands ``git format-patch`` and ``git send-email``.
    For information on how to use these scripts, see the
@@ -433,17 +433,12 @@
 following example Git commands::
 
    $ cd ~
-   $ git clone git://git.yoctoproject.org/poky
-   $ cd poky
-   $ git checkout -b &DISTRO_NAME_NO_CAP; origin/&DISTRO_NAME_NO_CAP;
+   $ git clone git://git.yoctoproject.org/poky -b &DISTRO_NAME_NO_CAP;
 
 In the previous example
 after moving to the home directory, the ``git clone`` command creates a
-local copy of the upstream ``poky`` Git repository. By default, Git
-checks out the "master" branch for your work. After changing the working
-directory to the new local repository (i.e. ``poky``), the
-``git checkout`` command creates and checks out a local branch named
-"&DISTRO_NAME_NO_CAP;", which tracks the upstream
+local copy of the upstream ``poky`` Git repository and checks out a
+local branch named "&DISTRO_NAME_NO_CAP;", which tracks the upstream
 "origin/&DISTRO_NAME_NO_CAP;" branch. Changes you make while in this
 branch would ultimately affect the upstream "&DISTRO_NAME_NO_CAP;" branch
 of the ``poky`` repository.
@@ -558,9 +553,9 @@
 -  *git pull --rebase:* Retrieves information from an upstream Git
    repository and places it in your local Git repository. You use this
    command to make sure you are synchronized with the repository from
-   which you are basing changes (.e.g. the "master" branch). The
-   "--rebase" option ensures that any local commits you have in your
-   branch are preserved at the top of your local branch.
+   which you are basing changes (e.g. the "&DISTRO_NAME_NO_CAP;"
+   branch). The "--rebase" option ensures that any local commits you
+   have in your branch are preserved at the top of your local branch.
 
 -  *git push repo-name local-branch:upstream-branch:* Sends
    all your committed local changes to the upstream Git repository that
@@ -571,13 +566,13 @@
 
 -  *git merge:* Combines or adds changes from one local branch of
    your repository with another branch. When you create a local Git
-   repository, the default branch is named "master". A typical workflow
-   is to create a temporary branch that is based off "master" that you
-   would use for isolated work. You would make your changes in that
-   isolated branch, stage and commit them locally, switch to the
-   "master" branch, and then use the ``git merge`` command to apply the
+   repository, the default branch may be named "main". A typical
+   workflow is to create a temporary branch that is based off "main"
+   that you would use for isolated work. You would make your changes in
+   that isolated branch, stage and commit them locally, switch to the
+   "main" branch, and then use the ``git merge`` command to apply the
    changes from your isolated branch into the currently checked out
-   branch (e.g. "master"). After the merge is complete and if you are
+   branch (e.g. "main"). After the merge is complete and if you are
    done with working in that isolated branch, you can safely delete the
    isolated branch.
 
diff --git a/poky/documentation/overview-manual/yp-intro.rst b/poky/documentation/overview-manual/yp-intro.rst
index 7aee9db..a8ca9e9 100644
--- a/poky/documentation/overview-manual/yp-intro.rst
+++ b/poky/documentation/overview-manual/yp-intro.rst
@@ -371,7 +371,7 @@
 
 -  *AutoBuilder:* AutoBuilder is a project that automates build tests
    and quality assurance (QA). By using the public AutoBuilder, anyone
-   can determine the status of the current "master" branch of Poky.
+   can determine the status of the current development branch of Poky.
 
    .. note::