docs: def file_list(self, saltenv='base', prefix=''):
          '''
          Return a list of files in the given environment
          with optional relative prefix path to limit directory traversal
          '''
          ret = []
          prefix = prefix.strip('/')
          for path in self.opts['pillar_roots'].get(saltenv, []):
              for root, dirs, files in salt.utils.path.os_walk(
                  os.path.join(path, prefix), followlinks=True
              ):
                  # Don't walk any directories that match file_ignore_regex or glob
                  dirs[:] = [d for d in dirs if not salt.fileserver.is_file_ignored(self.opts, d)]
                  for fname in files:
                      relpath = os.path.relpath(os.path.join(root, fname), path)
                      ret.append(salt.utils.data.decode(relpath))
          return ret