From Atlassian: The Atlassian Marketplace provides partners with access tokens that enable you to install and test apps under development in live cloud instances. This removes the need of having licenses generated through the Atlassian billing system.
Applying a token:
To use a token on an instance that already has the app installed in it:
Go for Apps ➡️ Manage your apps.
2. Find the add-on in the “User-installed apps” list and click on the arrow to open details.
3. Scroll down to the bottom ➡️ Open Settings ➡️ Checkmark Enable development mode (both options should be check-marked).
4. Go for Access token: {input token} ➡️ Access token status: Active trial
5. Check if the trial date is renewed.
Success 🎉