Web/HTTP/Status/421)
    42. [ ` 422 Unprocessable Content ` ](/en-US/docs/Web/HTTP/Status/422)
    43. [ ` 423 Locked ` ](/en-US/docs/Web/HTTP/Status/423)
    44. [ ` 424 Failed Dependency ` ](/en-US/docs/Web/HTTP/Status/424)
    45. [ ` 425 Too Early ` ](/en-US/docs/Web/HTTP/Status/425)
    46. _[ ` 426 Upgrade Required ` ](/en-US/docs/Web/HTTP/Status/426) _
    47. [ ` 428 Precondition Required ` ](/en-US/docs/Web/HTTP/Status/428)
    48. [ ` 429 Too Many Requests ` ](/en-US/docs/Web/HTTP/Status/429)
    49. [ ` 431 Request Header Fields Too Large ` ](/en-US/docs/Web/HTTP/Status/431)
    50. [ ` 451 Unavailable For Legal Reasons ` ](/en-US/docs/Web/HTTP/Status/451)
    51. [ ` 500 Internal Server Error ` ](/en-US/docs/Web/HTTP/Status/500)
    52. [ ` 501 Not Implemented ` ](/en-US/docs/Web/HTTP/Status/501)
    53. [ ` 502 Bad Gateway ` ](/en-US/docs/Web/HTTP/Status/502)
    54. [ ` 503 Service Unavailable ` ](/en-US/docs/Web/HTTP/Status/503)
    55. [ ` 504 Gateway Timeout ` ](/en-US/docs/Web/HTTP/Status/504)
    56. [ ` 505 HTTP Version Not Supported ` ](/en-US/docs/Web/HTTP/Status/505)
    57. [ ` 506 Variant Also Negotiates ` ](/en-US/docs/Web/HTTP/Status/506)
    58. [ ` 507 Insufficient Storage ` ](/en-US/docs/Web/HTTP/Status/507)
    59. [ ` 508 Loop Detected ` ](/en-US/docs/Web/HTTP/Status/508)
    60. [ ` 510 Not Extended ` ](/en-US/docs/Web/HTTP/Status/510)
    61. [ ` 511 Network Authentication Required ` ](/en-US/docs/Web/HTTP/Status/511)
  21. CSP directives 
    1. [ ` CSP source values ` ](/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/Sources)
    2. [ ` CSP: base-uri ` ](/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/base-uri)
    3. [ ` CSP: block-all-mixed-content ` ](/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/block-all-mixed-content) Deprecated 
    4. [ ` CSP: child-src ` ](/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/child-src)
    5. [ ` CSP: connect-src ` ](/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/connect-src)
    6. [ ` CSP: default-src ` ](/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/default-src)
    7. [ ` CSP: fenced-frame-src ` ](/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/fenced-frame-src) Experimental 
    8. [ ` CSP: font-src ` ](/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/font-src)
    9. [ ` CSP: form-action ` ](/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/form-action)
    10. [ ` CSP: frame-ancestors ` ](/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/frame-ancestors)
    11. [ ` CSP: frame-src ` ](/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/frame-src)
    12. [ ` CSP: img-src ` ](/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/img-src)
    13. [ ` CSP: manifest-src ` ](/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/manifest-src)
    14. [ ` CSP: media-src ` ](/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/media-src)
    15. [ ` CSP: object-src ` ](/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/object-src)
    16. [ ` CSP: plugin-types ` ](/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/plugin-types) Non-standard  Deprecated 
    17. [ ` CSP: prefetch-src ` ](/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/prefetch-src) Non-standard  Deprecated 
    18. [ ` CSP: referrer ` ](/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/referrer) Non-standard  Deprecated 
    19. [ ` CSP: report-to ` ](/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/report-to)
    20. [ ` CSP: report-uri ` ](/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/report-uri) Deprecated 
    21. [ ` CSP: require-trusted-types-for ` ](/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/require-trusted-types-for) Experimental 
    22. [ ` CSP: sandbox ` ](/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/sandbox)
    23. [ ` CSP: script-src ` ](/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/script-src)
    24. [ ` CSP: script-src-attr ` ](/en-US/docs/Web/HTTP/Headers/Content-Security-Pol