Setting an output parameter
Sets a step's output parameter. Note that the step will need an id to be defined to later retrieve the output value. You can set multi-line output values with the same technique used in the Multiline strings section to define multi-line environment variables.
echo "{name}={value}" >> "$GITHUB_OUTPUT"
Example of setting an output parameter
This example demonstrates how to set the SELECTED_COLOR output parameter and later retrieve it:
- name: Set color
id: color-selector
run: echo "SELECTED_COLOR=green" >> "$GITHUB_OUTPUT"
- name: Get color
env:
SELECTED_COLOR: ${{ steps.color-selector.outputs.SELECTED_COLOR }}
run: echo "The selected color is $SELECTED_COLOR"
Reference:
https://docs.github.com/en/actions/reference/workflows-and-actions/workflow-commands

Any actions or reusable workflows stored in the internal or private repository can be used in workflows defined in other internal or private repositories owned by the same organization, or by any organization owned by the enterprise.
Reference:
https://docs.github.com/actions/creating-actions/sharing-actions-and-workflows-with-your- enterprise

The pre: line before the pre-if: line.
Note: runs.pre-if
Optional
Allows you to define conditions for the pre: action execution. The pre: action will only run if the conditions in pre-if are met. If not set, then pre-if defaults to always(). In pre-if, status check functions evaluate against the job's status, not the action's own status.
Note that the step context is unavailable, as no steps have run yet.
In this example, cleanup.js only runs on Linux-based runners:
pre: 'cleanup.js'
pre-if: runner.os == 'linux'
Reference:
https://docs.github.com/en/actions/reference/workflows-and-actions/metadata-syntax

Manually running a workflow
When a workflow is configured to run on the workflow_dispatch event, you can run the workflow using the Actions tab on GitHub, GitHub CLI, or the REST API.
Configuring a workflow to run manually
To run a workflow manually, the workflow must be configured to run on the workflow_dispatch event.
To trigger the workflow_dispatch event, your workflow must be in the default branch.
Reference:
https://docs.github.com/en/actions/how-tos/manage-workflow-runs/manually-run-a-workflow

Publishing Docker images
The below workflow checks out the GitHub repository, uses the login-action to log in to the registry [B], and then uses the build-push-action action to: build a Docker image based on your repository's Dockerfile [E]; push the image to Docker Hub [A], and apply a tag to the image.
Note:
# This workflow uses actions that are not certified by GitHub.
# They are provided by a third-party and are governed by
# separate terms of service, privacy policy, and support
# documentation.
# GitHub recommends pinning actions to a commit SHA.
# To get a newer version, you will need to update the SHA.
# You can also reference a tag or branch, but the action may change without warning.
Reference:
https://docs.github.com/en/actions/tutorials/publish-packages/publish-docker-images