That's not a Discord bot, it's a Slack RSS App / RSS subscription.
Event Source: https://status.dev.azure.com/_event/543117809
It's pretty useful 'for work' because occasionally you'll get notifications when parts of infra might be down (like your build server)
No, not some internal company, just Microsoft being Microsoft. So all Windows pipelines. They also have Linux based pipelines so not completely all pipelines.
But given that a lot of people build dotnet stuff on Azure, the 'windows-latest' image is usually the default. So a lot of pipelines