Running build in debug mode

Another technique to debug build time issues is by running a debug build in Travis CI. You need to email [e-mail] to toggle this feature on for public repositories while private repositories have the debug mode enabled by default. The reason for this is that anyone can come across a log containing the SSH access and can then make a connection to the virtual machine and then potentially read out secret environment information, such as client IDs, secrets, and more.

Getting an API token from the profile page

To restart a job in debug mode via the API, you need to send a POST request to the job's debug endpoint. This request needs to be authenticated by adding your Travis CI API token...