Meddysong

It's here. @Jim_K:
https://invisioncommunity.com/forums/forum/499-feedback/

The menu is controlled via your Admin Control Panel, Bob:

Once you're there, it's fairly straightforward. There's a button Add item, which you'll use to create the new menu item. You'll have to choose what form it takes: is it a dropdown (= Drop-down Menu)? A link to a page (= Page)? A link to something else (= External link)? Have a play.
You can drag and drop your menu items to change their position. And any which you don't want can be sent on their way by hovering over them and then clicking the X:

Once you're happy with your menu, you click a button Publish this menu, and then it's applied to your site.

It's an unfortunate limitation of the system.
It is possible to change this by editing the core files, but this is not endorsed by IC, and could mean that they don't provide technical support should something go wrong with your site.
If you'd like to go ahead, you have to edit /applications/blogs/data/furl.json, changing the value of topLevel to whatever you want. (You can do the same with the other apps too, navingating to the correct folder from /applications.)

Nope, by design.

It turns out that the word keys don't become viewable, for some reason:

I've tracked it down on my own site. It's menutab__community_icon, and the value should be comments.

Confirming that upgrading to 4.7.4 fixed the similar error on my site. How about you, @clickco?

You have to create the folder beforehand for it to be selectable, Steve, so you need to go back to the Pages menu, and then click "Add Folder", which you will call "abax".
After that, you'll create a page, calling it whatever you like. Once the page exists and you've assigned its location to that folder, toggle open the "abax" folder on the Pages menu, and any posts you've created there will be listed. Click the down caret for the relevant page, and you'll see an option to make it the folder's default. That's the page which will appear at yoursite.com/abax. Any other pages in the folder will be at yoursite.com/abax/pagename.

But if you're trying to change just that one instance, then the easiest solution is to use the visual language editor:
 
 

You have to make the System app your default app, and then the Content Discovery module your default module within that app.
You can do this via System > Applications in the Admin Control Panel. Click the star next to System to make that your default module, and then open the dropdown to reveal the various modules within that app, clicking the star next to Content Discovery.

Adding
.ipsBreadcrumb_top { display: none; } to your custom CSS should be enough.

That's by design. It indicates that there isn't any unread content in that category. It's a visual hint to say "Look here!" if something's been added so that you don't have to check each category just in case. Are you sure you want to disable it?

Got it: sign out here, then go to the Client Area and sign out there too. This will bring up a pop-up for you to log in. Once you've done this, return to the Community, click "Sign in with email", and it will use the details that you logged into the Client Area with.
There's probably some room for improvement in this process. That was a frustrating few minutes wasted.

It can't be done automatically but Lindy has very kindly done exactly this for me once as a courtesy. You're a polite, helpful man and a regular contributor here, so I imagine he'd extend the same grace to you too if you submitted a ticket with the request for his attention.

Yes, but you need to know what the tags are, which makes things a bit challenging. {member_name} doesn't mean anything in this software, which is why it's not working for you. 
If you want to display a member's name, then you need:
{expression="\IPS\Member::loggedIn()->name"} or its shorthand version:
{expression="member.name"} I'm afraid I don't know where you can find a list of these expressions. My technique is to look for similar expressions in the templates and then experiment.

The plugin is defunct now that there is built-in functionality to create announcements, which you can access from the Create menu and the Moderator Control Panel:
 
 

That's not quite correct; you're missing { }:
@media screen and (max-width: 767px) { .ipsType_normal, .ipsType_medium, body { font-size: 17px; } }