I am working on a django project, and taking over the project from other developers as they have left the project. I came across a query which I am not able to understand how it works, This is the query in question.

provider_evaluations = ProviderEvaluation.objects.filter(
                    customer_provider_relation_id__projectproviders__project_id=project_id,
                    customer_provider_relation_id__provider_id=provider_id,

and these are the models included in the query.

class ProviderEvaluation(models.Model):
    provider_evaluation_criterias_id = models.ForeignKey(ProviderEvaluationCriterias, on_delete=models.CASCADE, null=True)
    evaluation = models.CharField(max_length=255, null=True)
    comment = models.TextField(null=True, blank=True)
    created_by = models.ForeignKey(get_user_model(), on_delete=models.CASCADE, null=True)
    workflow_step = models.ForeignKey(WorkflowStep, on_delete=models.CASCADE, default=None, null=True)
    customer_provider_relation_id = models.ForeignKey(CustomerProviderRelation, on_delete=models.CASCADE, null=True, default=None)

    def __str__(self):
        return f"{self.provider_evaluation_criterias_id} - {self.evaluation}"
    
class CustomerProviderRelation(models.Model):
    customer_tenant_type = models.ForeignKey(
        ContentType,
        on_delete=models.CASCADE,
        related_name='customer_tenant',
        limit_choices_to={'model__in': ['customer']},
    )
    provider_tenant_type = models.ForeignKey(
        ContentType,
        on_delete=models.CASCADE,
        related_name='provider_tenant',
        limit_choices_to={'model__in': ['provider']},
    )

    customer_tenant_id = models.PositiveIntegerField()
    provider_tenant_id = models.PositiveIntegerField()

    customer_tenant = GenericForeignKey('customer_tenant_type', 'customer_tenant_id')
    provider_tenant = GenericForeignKey('provider_tenant_type', 'provider_tenant_id')

    customer_id = models.ForeignKey(Customer, on_delete=models.CASCADE)
    provider_id = models.ForeignKey(Provider, on_delete=models.CASCADE)

    def save(self, *args, **kwargs):
        # Assign values to content type and object ID fields based on the instance being saved
        if isinstance(self.customer_tenant, Customer):
            self.customer_tenant_type = ContentType.objects.get_for_model(Customer)
            self.customer_tenant_id = self.customer_tenant.id
        if isinstance(self.provider_tenant, Provider):
            self.provider_tenant_type = ContentType.objects.get_for_model(Provider)
            self.provider_tenant_id = self.provider_tenant.id

        super().save(*args, **kwargs)

    def __str__(self):
        return f"CustomerProviderRelation ID: {self.id}"
    
class ProjectProviders(models.Model):
    STATE_CHOICES = [
        ('searched', 'Searched'),
        ('initiated', 'Initiated'),
        ('completed', 'Completed'),
        ('closed', 'Closed'),
        ('rejected', 'Rejected'),
    ]

    project_id = models.ForeignKey(Project, on_delete=models.CASCADE)
    customer_provider_relation_id = models.ForeignKey(CustomerProviderRelation, on_delete=models.CASCADE)
    shortlisted=models.BooleanField(default=False)
    state = models.CharField(max_length=20, choices=STATE_CHOICES)
    workflow_run_id = models.ForeignKey(WorkflowRun, on_delete=models.CASCADE,default=None)
    params = models.TextField()
    delisted = models.BooleanField(default = False)

    def __str__(self):
        return f"ProjectProviders ID: {self.id}"

I have tried running the query in django shell which returns the result, but I am not able to understand how, also I referred documentation but could not find what this type or query is called or how it works.