A new icon has been added to the popup panel, to open a popup
window with a terse list of DNR events for the current tab, in
reverse chronological order (most recent DNR event appears at
the top).
The new ability is available only when the extension is sideloaded,
as per `declarativeNetRequestFeedback` documentation. Ref:
https://developer.chrome.com/docs/extensions/reference/api/declarativeNetRequest#event-onRuleMatchedDebug
Purposefully minimal, so as to have something rather than nothing
when having to diagnose filtering issue with the DNR API. Example:
https://github.com/uBlockOrigin/uBOL-home/issues/156
The content of the popup window does not dynamically update, force
a refresh (F5) to get the most recent DNR events. This might be
improved in the future.
The DNR event buffer is not persisted, so the buffer is empty when
service worker is restarted. This might be improved in the future
by using session storage API.
There is no output filtering ability in this first draft. This
might be improved in the future.
DNR rules are reported. The filter from which a DNR rule
originates is not reported. Given that the rulesets are optimized
after conversion from original filter lists to reduce the DNR rule
count, this is unlikely to ever be possible.
