in alloydb-jdbc-connector/src/main/java/com/google/cloud/alloydb/ServiceAccountImpersonatingCredentialFactory.java [63:74]
public GoogleCredentials getCredentials() {
GoogleCredentials credentials = source.getCredentials();
credentials =
ImpersonatedCredentials.newBuilder()
.setSourceCredentials(credentials)
.setTargetPrincipal(targetPrincipal)
.setDelegates(this.delegates)
.setScopes(Arrays.asList(SCOPE_CLOUD_PLATFORM))
.build();
return credentials;
}