'Default access token' doesn't seem to allow link previews at all

Hi

I want to enable link previews in Nextcloud documents for Github issues that are in private repositories.

I don't wish for my Nextcloud users to connect their own Github accounts to their Nextcloud accounts via OAuth.

I created a personal access token (the 'beta' kind, with finely scoped Read-Only access to: code, discussions, issues, metadata, and pull requests

I added that PAT to the global administrative settings in Nextcloud under settings/admin/connected-accounts as the 'Default access token'.

I ticked the box 'Enable Github link previews'

I still get 'Github API error Not Found' widgets appear in my documents when I paste a link to a Github issue in a private repository that this Github user has access to. The widget wants me to go to my personal account settings in Nextcloud to configure Github access, but I thought the 'default' access token should take care of it.

What's the problem? Is it the beta 'fine-grained' PAT method? I don't want to use the Classic method because I don't want Nextcloud to have write access to private repos through this token.

Otherwise, what are the scopes required for the PAT to work, with the beta method?

Do I still have to set up an OAuth2.0 app even though my use case is limited to link previews?

I am running Nextcloud 25.0.8, Github integration app 1.0.15

Start at the settings/admin/connected-accounts flow and the “Enable Github link previews” setting, then reproduce the Not Found response with a fine-grained read-only token on Nextcloud 25.0.8 and GitHub integration app 1.0.15. Done means determining whether the default token is supported for private issue previews, identifying the required scopes or OAuth requirement, and documenting or correcting the behavior.