Bugzilla

Yes, the Page Info window is quite hidden without a default menubar and the identity/permissions panels and popups provide similar features, for WebRTC at least, with the difference that adding explicit block and allow features is only possible when the feature is requested by content.  (In some ways that has similarities with Page Info being available for a domain only while a page is loaded from that domain.)  Good to understand that Page Info is not so important now, thanks.

This is reproducible without the Page Info window, however, by replacing step 4 with

4.1 Open testcase in a second tab.
4.2 Click "getUserMedia".
4.3 Select "Remember this decision".
4.4. Select Block.

and replacing step 7 with

7. Remove "Blocked" "Use the microphone" permission from the identity permission panel in the second tab.

The same inconsistency in steps 5 and 6 demonstrates in the first tab.
Perhaps arguably the same actual behavior after steps 8 and 9 feels more expected with the UI being associated with a different tabs.

Yes, the Page Info window is quite hidden without a default menubar and the identity/permissions panels and popups provide similar features, for WebRTC at least, with the difference that adding explicit block and allow features is only possible when the feature is requested by content.  (In some ways that has similarities with Page Info being available for a domain only while a page is loaded from that domain.)  Good to understand that Page Info is not so important now, thanks.

This is reproducible without the Page Info window, however, by replacing step 4 with

4.1 Open testcase in a second tab.
4.2 Click "getUserMedia".
4.3 Select "Remember this decision".
4.4. Select Block.

and replacing step 7 with

7. Remove "Blocked" "Use the microphone" permission from the identity permission panel in the second tab.

The same inconsistency in steps 5 and 6 demonstrates in the first tab.
Perhaps arguably the same actual behavior after steps 8 and 9 feels more expected with the UI being associated with different tabs.