https://firefox-source-docs.mozilla.org/devtools-user/network_monitor/toolbar/index.html

https://firefox-source-docs.mozilla.org/devtools-user/network_monitor/request_list/
https://firefox-source-docs.mozilla.org/devtools-user/network_monitor/request_list/#filtering-by-properties
    C+F
    domain:bla.bla
    status-code:
    mime-type
    cause:img

    regexp:\d{5}
    regexp:mdn|mozilla
        https://en.wikipedia.org/wiki/Regular_expression
        https://regexone.com/
        https://regexper.com

2020
https://alan.norbauer.com/articles/browser-debugging-tricks