`GET /api/v1/users/{username}/heatmap` computed the contribution heatmap with the repository access of the token owner and ignored the public-only restriction of the access token, unlike the activity feed endpoints. A holder of a user's public-only token could read contribution counts and their 15-minute time buckets that stem from that user's activity in private repositories. Repository names and contents were not disclosed. For public-only tokens the heatmap now only counts activity visible to anonymous users.
https://github.com/go-gitea/gitea/security/advisories/GHSA-jr76-w9m3-3p68
https://github.com/go-gitea/gitea/releases/tag/v28.3.0
https://github.com/go-gitea/gitea/pull/39853