在下面收集的ABNF中，列表规则根据[RFC7230]的第1.2节进行了扩展。

    1.    ETag = entity-tag
    3.    HTTP-date = <HTTP-date, see [RFC7231], Section 7.1.1.1>
    5.    If-Match = "*" / ( *( "," OWS ) entity-tag *( OWS "," [ OWS
    6.     entity-tag ] ) )
    7.    If-Modified-Since = HTTP-date
    8.    If-None-Match = "*" / ( *( "," OWS ) entity-tag *( OWS "," [ OWS
    9.     entity-tag ] ) )
    10.    If-Unmodified-Since = HTTP-date
    12.    Last-Modified = HTTP-date
    14.    OWS = <OWS, see [RFC7230], Section 3.2.3>
    16.    entity-tag = [ weak ] opaque-tag
    17.    etagc = "!" / %x23-7E ; '#'-'~'
    18.     / obs-text
    20.    obs-text = <obs-text, see [RFC7230], Section 3.2.6>
    21.    opaque-tag = DQUOTE *etagc DQUOTE
    23.    weak = %x57.2F ; W/