diff --git a/docs/contributor/unit-tests/README.md b/docs/contributor/unit-tests/README.md
new file mode 100644
index 000000000..b33309d0f
--- /dev/null
+++ b/docs/contributor/unit-tests/README.md
@@ -0,0 +1,89 @@
+# PHP Unit tests
+
+GatherPress allows to run **automated & manual php unit tests**, while sharing the same, `wp-env` based, setup.
+
+## Automated tests
+
+Check the results of the [*phpunit-tests action workflow*](https://github.com/GatherPress/gatherpress/actions/workflows/phpunit-tests.yml) at `https://github.com/GatherPress/gatherpress/actions/workflows/phpunit-tests.yml`.
+
+## Manual tests
+
+The unittest-setup can also be used to manually run the test suite. In general, only a `wp-env` instance is needed.
+
+### Install dependencies
+
+To run the unit tests you will have to install the requirements using the following commands:
+
+```bash
+composer install
+```
+
+> [!NOTE]
+> You also need to use Node.js 20 or later
+
+Install the dependencies to create the Playground testing instance, using the following command:
+
+```bash
+npm ci --legacy-peer-deps
+```
+
+### Start the Environment
+
+A call to `npm run test:unit:php` will automatically setup a `wp-env` powered WordPress instance, already prepared to mount GatherPress from the current directory.
+
+So while there is no technical need to start `wp-env` manually on its own, you might want to do so for any reason. If the environment is already running, the unit tests will run against that existing instance. You might want to start it with this command:
+
+
+```bash
+npm run wp-env -- start
+```
+
+The testing website is reachable at `http://127.0.0.1:8889`, the user is `admin` and the password is `password`. 
+
+### Run the unit tests
+
+To run the full suite with all unit tests, use the command:
+
+```bash
+npm run test:unit:php
+```
+
+To run only specific tests, you can call `npm run test:unit:php`:
+
+- with the `--filter` argument,
+    to execute all tests in `test/unit/php/includes/core/classes/class-test-event-query.php` for example:
+
+    ```bash
+    npm run test:unit:php -- --filter 'Test_Event_Query'
+    ```
+
+- with the `--group` argument, to execute all tests which share the same `@group` declaration, for example all tests related to `/ical` and `/feed/ical` endpoints of events & venues:
+
+    ```bash
+    npm run test:unit:php -- --group endpoints
+    ```
+
+- or with any other of [phpunit's command-line options](https://docs.phpunit.de/en/10.5/textui.html#command-line-options).
+
+## Resources
+
+### PMC Unit Test Framework
+
+GatherPress uses the *PMC Unit Test Framework* because it:
+
+> [...] provide[s] common utilities and data mocking for unit tests in a WordPress environment.
+
+> This plugin was originally written for internal use at Penske Media [...] Our hope is that other teams find this plugin as useful as we do when writing unit tests in WordPress.
+>
+> <https://github.com/penske-media-corp/pmc-unit-test>
+
+- [Installation](https://github.com/penske-media-corp/pmc-unit-test/tree/main?tab=readme-ov-file#installation)
+- [Usage](https://github.com/penske-media-corp/pmc-unit-test/tree/main?tab=readme-ov-file#usage)
+- [Data Mocking Overview](https://github.com/penske-media-corp/pmc-unit-test/blob/main/src/mocks/README.md)
+    - [$this->mock->http()](https://github.com/penske-media-corp/pmc-unit-test/blob/main/docs/mock-http.md)
+    - [$this->mock->input()](https://github.com/penske-media-corp/pmc-unit-test/blob/main/docs/mock-input.md)
+    - [$this->mock->mail()](https://github.com/penske-media-corp/pmc-unit-test/blob/main/docs/mock-mail.md)
+    - [$this->mock->post()](https://github.com/penske-media-corp/pmc-unit-test/blob/main/docs/mock-post.md)
+    - [$this->mock->post()->is_amp()](https://github.com/penske-media-corp/pmc-unit-test/blob/main/docs/mock-post.md)
+    - [$this->mock->user()](https://github.com/penske-media-corp/pmc-unit-test/blob/main/docs/mock-user.md)
+    - [$this->mock->wp()](https://github.com/penske-media-corp/pmc-unit-test/blob/main/docs/mock-wp.md)
diff --git a/docs/developer/README.md b/docs/developer/README.md
index 96c35b6e2..286b36c27 100644
--- a/docs/developer/README.md
+++ b/docs/developer/README.md
@@ -65,7 +65,7 @@ cd gatherpress
 wp-env start
 ```
 
-You should then see that a development site has been configured for you on localhost port 2003
+You should then see that a development site has been configured for you on localhost port 8889
 
 ![Development Site Login](../media/wp-env.json-startup.png)