El identificador externo web.assets_backend no se encuentra en Odoo 15.

Cuando intenté heredar el ID externo web.assets_backend, Odoo dice que no se encontró el ID externo. Aquí está el registro de errores:

Traceback (most recent call last):
  File "/opt/odoo/sources/odoo/odoo/tools/cache.py", line 85, in lookup
    r = d[key]
  File "/opt/odoo/sources/odoo/odoo/tools/func.py", line 71, in wrapper
    return func(self, *args, **kwargs)
  File "/opt/odoo/sources/odoo/odoo/tools/lru.py", line 34, in __getitem__
    a = self.d[obj]
KeyError: ('ir.model.data', <function irmodeldata._xmlid_lookup="" at="" 0x7fb3865beaf0="">, 'web.assets_backend')

Durante el manejo de la excepción anterior, ocurrió otra excepción:

Traceback (most recent call last):
  File "/opt/odoo/sources/odoo/odoo/tools/convert.py", line 680, in _tag_root
    f(rec)
  File "/opt/odoo/sources/odoo/odoo/tools/convert.py", line 658, in _tag_template
    return self._tag_record(record)
  File "/opt/odoo/sources/odoo/odoo/tools/convert.py", line 567, in _tag_record
    f_val = self.id_get(f_ref)
  File "/opt/odoo/sources/odoo/odoo/tools/convert.py", line 663, in id_get
    res = self.model_id_get(id_str, raise_if_not_found)
  File "/opt/odoo/sources/odoo/odoo/tools/convert.py", line 669, in model_id_get
    return self.env['ir.model.data']._xmlid_to_res_model_res_id(id_str, raise_if_not_found=raise_if_not_found)
  File "/opt/odoo/sources/odoo/odoo/addons/base/models/ir_model.py", line 1935, in _xmlid_to_res_model_res_id
    return self._xmlid_lookup(xmlid)[1:3]
  File "<decorator-gen-35>", line 2, in _xmlid_lookup
  File "/opt/odoo/sources/odoo/odoo/tools/cache.py", line 90, in lookup
    value = d[key] = self.method(*args, **kwargs)
  File "/opt/odoo/sources/odoo/odoo/addons/base/models/ir_model.py", line 1928, in _xmlid_lookup
    raise ValueError('External ID not found in the system: %s' % xmlid)
ValueError: External ID not found in the system: web.assets_backend

¿Cuál es la solución para este problema? Gracias de antemano.