The grafana plugin SDK bundles build metadata into the binaries it compiles; this metadata includes the repository URI for the plugin being built, as retrieved by running git remote get-url origin.
If credentials are included in the repository URI (for instance, to allow for fetching of private dependencies), the final binary will contain the full URI, including said credentials.
The product transmits or stores authentication credentials, but it uses an insecure method that is susceptible to unauthorized interception and/or retrieval.