The API Specification Toolbox is a community project and runs 100% on Github so that anyone can submit a pull request and add or update any of the extensions listed here on the toolbox. You can find the extensions all listed in the _extensions folder in the repo, and each tool has a single YAML file stored as an .md file. Using YAML front end matter to publish the data to the listing and detail pages.
To update or add extensions to the site, you can fork the repository for the project, add or update any of the files, and then submit a pull request with all the changes. See the examples in the `_extensions` dirctory. Add corresponding images to the `images/extensions` directory using images with ~354x184 landscape aspect ratio. See the main source `README.md` file for instructions to preview your work locally.
If you don't feel comfortable submitting a pull request you can just submit an issue using the "new-extensions" label. If you are looking to help, we can really use assistance with some data entry, adding any of the existing extensions that have been submitted as a Github issue--we really appreciate the community contribution.