2.1.114 [HTML5:2014] Section Parsing cache manifests

V0263: The settings parse mode is not supported

The specification states:

 ... Parsing cache manifests
     When a user agent is to parse a manifest, it means that the user agent must run the 
     following steps:
         ...  Process tokens as follows:
                 If mode is "settings"
                     If tokens contains a single token, and that token is a case-sensitive 
                     match for the string "prefer-online", then set cache mode flag to 
                     prefer-online and jump back to the step labeled start of line.
                     Otherwise, the line is an unsupported setting: do nothing; the line 
                     is ignored.

All document modes (All versions)

The settings parse mode is not supported.