Consider changing block/blacklist device to be "reject device", with associated UX improvements

[ara4n]

The word 'blacklist' is still not entirely working for me - it feels too jargony and still contains massive connotations of stopping you from receiving messages rather than sending them.

I wonder if "reject device" might be better - especially in the context of the new warn-unknown-device stuff, where you would then get warnings of the form "Someone has added a new device to the room - do you want to reject it?"

I'm also wondering if this idiom could then potentially entirely replace the blacklist-unverified config options which I PR'd last night (matrix-org/matrix-react-sdk#636). Currently this provides checkboxes in UserSettings & RoomSettings to enable "blacklist unverified" mode. Perhaps this is unnecessary and needlessly hidden, though, as if the UnknownDeviceDialog went and just had a button for "reject all unverified devices" at the bottom it might be unnecessary - making the user spell out whether to reject for new devices (but positioning it almost as the default option).

This would then gather all the device trust management into a single dashboard dialog, so when new devices are added into a room, you'd get the dialog, but it would:

• Show all the unverified devices in the room (and possibly the verified ones too for completeness) - rather than the subset of just 'unknown' ones we show atm? This gives the user better visibility and also keeps reminding them which unverified devices they hanging around.
• Give the option to bulk-reject in a room every time new devices come up. It's not /quite/ as safe as silently that without prompting the user, but it's a bit more predictable and less magical.

@richvdh wdyt?

[ara4n]

/me gently pings @richvdh at low priority

[richvdh]

I looked briefly at this today. There seem to be several questions on the table:

• should we replace 'blacklist [device]' with 'reject [device]'? I'm just not convinced this is an improvement. It still sounds like we won't accept any messages from that device.

• In the unknown devices dialog, should we have a "{blacklist|reject} all" button, possibly instead of the "blacklist unverified" setting. Maybe? It might help discoverability.

• Should we have a single dashboard for "devices you have verified/{blacklisted|rejected}"? sure we should. Raised as Dashboard for managing blocked/verified status of e2e devices #4157.

[richvdh]

It still sounds like we won't accept any messages from that device.

Of course, maybe we should. If we don't trust the device enough to send it messages, perhaps we also shouldn't accept messages from it. Doesn't entirely follow, but it might help fix the UX.

That's still orthogonal to whether we label it 'blacklist' or 'reject', though...