docs: def get_applicable_overlays(self, error_bundle):
          """
          Given an error bundle, a list of overlays that are present in the
          current package or subpackage are returned.
          """
  
          content_paths = self.get_triples(subject='content')
          if not content_paths:
              return set()
  
          # Create some variables that will store where the applicable content
          # instruction path references and where it links to.
          chrome_path = ''
          content_root_path = '/'
  
          # Look through each of the listed packages and paths.
          for path in content_paths:
              chrome_name = path['predicate']
              if not path['object']:
                  continue
              path_location = path['object'].strip().split()[0]
  
              # Handle jarred paths differently.
              if path_location.startswith('jar:'):
                  if not error_bundle.is_nested_package:
                      continue
  
                  # Parse out the JAR and it's location within the chrome.
                  split_jar_url = path_location[4:].split('!', 2)
                  # Ignore invalid/unsupported JAR URLs.
                  if len(split_jar_url) != 2:
                      continue
  
                  # Unpack the JAR URL.
                  jar_path, package_path = split_jar_url
  
                  # Ignore the instruction if the JAR it points to doesn't match
                  # up with the current subpackage tree.
                  if jar_path != error_bundle.package_stack[0]:
                      continue
                  chrome_path = self._url_chunk_join(chrome_name, package_path)
                  # content_root_path stays at the default: /
  
                  break
              else:
                  # If we're in a subpackage, a content instruction referring to
                  # the root of the package obviously doesn't apply.
                  if error_bundle.is_nested_package:
                      continue
  
                  chrome_path = self._url_chunk_join(chrome_name, 'content')
                  content_root_path = '/%s/' % path_location.strip('/')
                  break
  
          if not chrome_path:
              return set()
  
          applicable_overlays = set()
          chrome_path = 'chrome://%s' % self._url_chunk_join(chrome_path + '/')
  
          for overlay in self.get_triples(subject='overlay'):
              if not overlay['object']:
                  error_bundle.error(
                      err_id=('chromemanifest', 'get_applicable_overalys',
                              'object'),
                      error='Overlay instruction missing a property.',
                      description='When overlays are registered in a chrome '
                                  'manifest file, they require a namespace and '
                                  'a chrome URL at minimum.',
                      filename=overlay['filename'],
                      line=overlay['line'],
                      context=self.context)  #TODO(basta): Update this!
                  continue
              overlay_url = overlay['object'].split()[0]
              if overlay_url.startswith(chrome_path):
                  overlay_relative_path = overlay_url[len(chrome_path):]
                  applicable_overlays.add('/%s' %
                          self._url_chunk_join(content_root_path,
                                               overlay_relative_path))
  
          return applicable_overlays