Assets was originally a separate app acquired by Atlassian and later integrated into Jira. Some technical hurdles remain, preventing us from retrieving Asset information via known APIs. We implemented a workaround to display Asset fields.
You can enable this using the “Native portal look & feel” setting in our Customer Portal app
After activating the setting, assets appear within your requests.
If you like to know more about how to create an API token as a user in Jira, see: Teams portal app: How can I create an API token to enable Asset field support?
See our support doc to learn more about portal settings: Teams-Portal-Settings