This problem analyzer helps you deploy changes to Flow Definitions.
What triggers this problem analyzer?
If you're using version 44 (Winter '19) of the metadata API to compare and deploy your metadata AND you include any Flow Definitions, we'll warn you.
What problem is this analyzer solving?
One reason to stop using them is that Flow version numbers aren't carried across between environments, so there's no guarantee that version 2 of the Flow in the source organization is the same as version 2 in the target organization! This also means that your source Flow Definition can specify an active version that isn't present in the target.
If you try to deploy a Flow Definition that references an invalid version number as the active version, your deployment will fail.
How does it work?
We'll show you a warning. This will then let you decide whether to deploy the Flow Definitions or remove them from your deployment.