Improve developer docs for local builds (#5699) [ci skip]

Signed-off-by: Ben Sherman <[email protected]>

docs/developer/index.md

@@ -106,13 +106,13 @@ Once complete, you can run your local build of Nextflow using the `launch.sh` sc
 ./launch.sh run <script> ...
 ```
 
-A self-contained executable Nextflow package can be created with the following command:
+Alternatively, you can build a self-contained executable with the following command:
 
 ```bash
 make pack
 ```
 
-Again, use `launch.sh` in place of the `nextflow` command to use your local build.
+It will create a binary in the `build/releases` directory which can be used in place of `nextflow`. This approach is useful when testing a pipeline that uses third-party plugins, which is not supported by `launch.sh`.
 
 ## Testing
 
@@ -132,14 +132,6 @@ When a test fails, it will give you a report that you can open in your browser t
 
 Refer to the [build.yml](https://github.com/nextflow-io/nextflow/tree/master/.github/workflows/build.yml) configuration to see how to run integration tests locally, if you are interested.
 
-## Installing from source
-
-The `nextflow` command is just a Bash script that downloads and executes the Nextflow JAR. When you install Nextflow using `get.nextflow.io`, it only downloads this launcher script, while the Nextflow JAR is downloaded on the first Nextflow run.
-
-You can run `make install` to install a local build of the Nextflow JAR to `$NXF_HOME`. Note that this command will overwrite any existing Nextflow packages with the same version. This approach is useful for testing non-core plugins with a local build of Nextflow.
-
-If you need to test changes to the `nextflow` launcher script, you can run it directly as `./nextflow`, or you can install it using `cp nextflow $(which nextflow)` and then run it as `nextflow`.
-
 ## Debugging
 
 ### Groovy REPL