Coverage chart / Xcode
Floodtide does not update Xcode
Xcode is a Mac App Store title whose download is far too large to update inside Floodtide. Rather than leave you to find that out after paying, here is the whole reason.
Why not
Floodtide updates App Store apps in place since 1.3.0, but not this one. Any store app whose download runs past about 675 MB is handed to the App Store on purpose: an update that ran for hours inside Floodtide would tell you less about its progress than the store itself does, and would be harder to stop. Xcode is several gigabytes, so its row keeps an Open in App Store button and the pending version beside it, which is still more than the App Store tells you on its own.
Floodtide shows you that Xcode has an update waiting and takes you straight to it. Apple installs it.
Floodtide also reads the Sparkle feed of any installed app that publishes one, which is a separate path from the Homebrew list. If Xcode ships a Sparkle feed on your Mac, it will appear in your update list even though it is not on the coverage chart.
What this says about the rest
MacUpdater kept a hand-maintained database of every Mac app, which is why it could claim near total coverage right up until the day it could not maintain it any more. Floodtide reads sources the vendors already keep current, so the coverage list is smaller and it does not go stale. The trade is deliberate: a shorter list you can trust beats a longer one you cannot check.
Questions about Xcode
Does Floodtide update Xcode?
No. Xcode is a Mac App Store title whose download is far too large to update inside Floodtide. Floodtide updates App Store apps in place since 1.3.0, but not this one. Any store app whose download runs past about 675 MB is handed to the App Store on purpose: an update that ran for hours inside Floodtide would tell you less about its progress than the store itself does, and would be harder to stop. Xcode is several gigabytes, so its row keeps an Open in App Store button and the pending version beside it, which is still more than the App Store tells you on its own.
Will Floodtide ever cover Xcode?
Only if its download gets far smaller, which is not something a vendor does. The size limit is there so a multi-hour install never runs somewhere that shows you less about it than the App Store does.
Does Floodtide hide apps it cannot update?
No. Floodtide shows an app it cannot handle with the reason attached, in the app and here. An updater that quietly omits what it cannot do is one you cannot use to answer the question "is this Mac up to date", which is the only question that matters.