Execute the following command in a *Console*. Replace <span class="command-placeholder">application</span> with the command line of the application that you want to open.
For example, to add the `non-free` sections of Debian 13 (Trixie), backports, and security updates, you can create a file named */live/persistence/TailsData_unlocked/apt-sources.list.d/non-free.list* with the following content: