Apps can ask you to pick a Slack channel
An app that works with Slack can now use your workspace's Slack connection and offer a channel picker in its settings.
Apps can now work with Slack through your workspace's Slack connection, and an app that needs a channel can ask for one directly. Its settings show a picker listing the channels available to that connection, so there is no channel ID to look up in Slack and paste in.
If Slack is not connected yet, the setting shows a Connect to Slack button that takes you to Settings > Integrations, rather than failing later.